//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8833 SUBJECT: AXP 1E1547.0-5408 activity with SGR bursts DATE: 09/01/22 02:25:39 GMT FROM: David Palmer at LANL C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU) and L. Vetere (PSU) report on behalf of the Swift Team: At 01:32:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located the known Anomalous X-Ray Pulasr AXP 1E1547.0-5408 (trigger=340573). Swift could not slew to this burst due to Earth limb constraint. The BAT on-board calculated location is RA, Dec 237.705, -54.320 which is RA(J2000) = 15h 50m 49s Dec(J2000) = -54d 19' 10" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed the typical short (<128 ms) spike of a Soft Gamma Repeater. The peak count rate was ~30,000 counts/sec (15-350 keV), at ~0 sec after the trigger. There are additional similar bursts visible in the light curve at T-40 and T+160 seconds. In addition at least 4 similar bursts had been seen by the Fermi GBM in the previous hour. An additional burst triggered BAT at T+37 minutes (Trigger 340578) which showed a multiple peak structure with a maximum count rate of 170,000 counts/s. SGR bursts from this source were last seen in early October 2008. XRT and UVOT will observe this source when it emerges from Earth limb constraint at 02:23 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8835 SUBJECT: AXP 1E1547.0-5408: Fermi GBM observations DATE: 09/01/22 08:39:21 GMT FROM: Valerie Connaughton at MSFC Valerie Connaughton (UAH) and Michael Briggs (UAH) report on behalf of the Fermi GBM Team: "At 00:53:52.17 UT on 22 Jan 2009, the Fermi Gamma-Ray Burst Monitor triggered on AXP 1E1547.0-5408 (trigger 254278434 / 090122037). Since then, GBM has seen 18 triggers from this source including one trigger also detected by the Swift-BAT (Palmer et al. 2009, GCN 8833). The trigger rate is consistent with constant source activity in the form of short and often very bright pulses occurring within an interval of a few seconds to about 150s between pulses. We estimate the source activity is constant because the time between triggers is between 600s and 740s outside of SAA passages and periods during which the source is occulted by the Earth. The minimum possible trigger spacing for GBM is 596 seconds. Because of the high data rate these triggers have caused, it is not yet possible to perform spectral analysis of any of these events. We estimate from our real-time data, however, that the source is visible at least up to 100 keV and is not visible above 300 keV." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8837 SUBJECT: AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase DATE: 09/01/22 16:22:32 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve V. Savchenko, V. Beckmann, A. Neronov (ISDC), S. Mereghetti (INAF/IASF-Milano), A. von Kienlin (MPE), M. Beck (ISDC), J. Borkowski (CAMK/Torun), D. Gotz (CEA/Saclay) report on behalf of the INTEGRAL SPI-ACS GRB team: The SPI Anti-Coincidence System (ACS) on-board INTEGRAL has detected burst activity most likely arising from the AXP 1E1547.0-5408, as reported based on Swift/BAT (GCN 8834, 8833) and Fermi GBM data (GCN 8835). From 2009-01-22T00:42:05 until 10:49:56 UT, 167 short (from 50ms to 8s) intense bursts were detected with significance from 5 to 160 sigma (1e4 - 2e6 counts/s peak count rate). The SPI-ACS light curves of triggered events are available (both as images and data files) at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi The light curves, binned at 50 ms, are derived from 91 independent detectors with different lower energy thresholds (mainly between 50 keV and 150 keV) and an upper threshold at about 100 MeV. The ACS response varies as a function of the GRB incident angle. For these reasons we caution that the count rates cannot be easily translated into physical flux units. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8838 SUBJECT: AXP 1E1547.0-5408: Fermi GBM detection of additional bursts DATE: 09/01/22 16:27:07 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) and V. Connaughton (UAH) report on behalf of the Fermi GBM Team: "Since the first 18 triggers from AXP 1E1547.0-5408 detected by the Fermi Gamma-ray Burst Monitor on 22 January 2009 (GCN 8835, Connaughton & Briggs), there have been 13 additional triggers of Fermi GBM from this source. The GBM on-board locations are all consistent with the AXP 1E1547.0-5408 position. So there are a total of 31 triggered bursts from this source. Many other bursts were recorded during times where GBM was still in trigger mode. List of all GBM triggers since the first trigger on 00:53:52.17 UT: # Trigcat Trigger UTC ---------------------------------------------- 1 GBM 090122.037 254279434 00:53:52.17 2 GBM 090122.044 254279035 01:03:53.93 3 GBM 090122.052 254279656 01:14:14.88 4 GBM 090122.059 254280306 01:25:04.31 5 GBM 090122.104 254284211 02:30:09.39 6 GBM 090122.113 254284945 02:42:23.17 7 GBM 090122.120 254285611 02:53:29.75 8 GBM 090122.129 254286352 03:05:50.39 9 GBM 090122.173 254290113 04:08:31.65 10 GBM 090122.180 254290769 04:19:27.62 11 GBM 090122.187 254291369 04:29:27.73 12 GBM 090122.194 254291971 04:39:29.95 13 GBM 090122.218 254294023 05:13:41.02 14 GBM 090122.243 254296159 05:49:17.55 15 GBM 090122.252 254297017 06:03:36.00 16 GBM 090122.283 254299678 06:47:56.78 17 GBM 090122.291 254300306 06:58:24.25 18 GBM 090122.310 254301991 07:26:29.66 19 GBM 090122.317 254302590 07:36:28.75 20 GBM 090122.352 254305576 08:26:14.53 21 GBM 090122.359 254306192 08:36:30.55 22 GBM 090122.380 254308060 09:07:38.67 23 GBM 090122.390 254308862 09:21:00.39 24 GBM 090122.419 254311386 10:03:04.66 25 GBM 090122.428 254312201 10:16:39.36 26 GBM 090122.451 254314172 10:49:30.19 27 GBM 090122.491 254317583 11:46:21.33 28 GBM 090122.498 254318256 11:57:34.06 29 GBM 090122.551 254322796 13:13:14.53 30 GBM 090122.584 254325635 14:00:33.44 31 GBM 090122.624 254329074 14:57:52.72 Spectral analysis results will be reported soon." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8841 SUBJECT: AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS DATE: 09/01/22 20:38:00 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti (INAF/IASF-Milano), D. Gotz (CEA/Saclay), A. von Kienlin (MPE), V. Beckmann, V. Savchenko, A. Neronov, M. Beck (ISDC), J.Borkowski (CAMK/Torun) report on behalf of the INTEGRAL SPI-ACS GRB team: On 2009 Jan 22, the SPI Anti-Coincidence System (ACS) on-board INTEGRAL recorded two bright and long bursts from the AXP 1E1547.0-5408 that recently reactivated (GCN 8833, 8835, 8837, 8838). In both bursts, pulsations at the neutron star period of 2.1 s are clearly visible The start times, duration, and ACS peak count rates (Dt=50 ms) are the following: 1) 06:48:04.2 UT 8.4 s 1.5 10^6 cts/s 2) 08:17:29.4 UT 6.4 s 1.9 10^5 cts/s Burst 1) consists of a short inital spike, lasting about 0.25 s, followed by a pulsating tail. The light curves are available at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8845 SUBJECT: AXP 1E1547.0-5408: Suzaku WAM detections of the current activity DATE: 09/01/23 15:56:03 GMT FROM: Kazutaka Yamaoka at Aoyama Gakuin U Y. Terada, M. Tashiro, Y. Urata, A. Endo, K. Onda, N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), Y.E. Nakagawa, T. Tamagawa (RIKEN), T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.), E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono, H. Hayashi, (Univ. of Miyazaki), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech), on behalf of the Suzaku WAM team, report: The Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV detected the current burst activities most likely arising from the AXP 1E1547.0-5408, as reported by Swift BAT (Gronwall et al., GCN 8833), INTEGRAL SPI-ACS (Savchenko et al., GCN 8837) and Fermi GBM (Connaughton et al., GCN 8835). Over a period of January 21 23:49:41 - January 22 23:47:00 (UT), the WAM detected about 250 bursts with durations of less than 5 seconds above 5.5 sigma. The most intense event with a T90 duration of 5 seconds was observed on 2009-01-22 08:17:28 (UT), and also detected by INTEGRAL SPI-ACS (Mereghetti et al., GCN 8841). The light curves with 1 sec time resolution for all these bursts are available at the following URL: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/sgraxp/untrig/sgraxp_table_2009.html Among them, following five events were detected with the Suzaku WAM onboard triggering system, and their finer time resolution light curves (1/64 sec time resolution) are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/sgraxp/trig/sgraxp_table_2009.html -------------------------------------------------------------------------- Trigger Time (UT) T90 duration (s) -------------------------------------------------------------------------- 2009-01-22 01:28:59 0.14 2009-01-22 02:46:56 1.5 2009-01-22 04:34:52 0.41 (the first event) 2.0 (the second event including its precursor) 2009-01-22 15:10:34 0.13 2009-01-22 17:02:55 0.36 -------------------------------------------------------------------------- Spectral analyses are now in progress, and results will be reported later. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8848 SUBJECT: 1E1547.0-5408: Swift detection of dust halo DATE: 09/01/24 00:52:59 GMT FROM: Sandro Mereghetti at IASF/CNR A.Tiengo, S.Mereghetti, G.Vianello, P.Esposito (INAF-IASF Milano), G.L.Israel (INAF-OAR), N.Rea (Amsterdam Univ.), D.Gotz (CeA Saclay), on behalf of a larger collaboration report: A Swift/XRT observation performed on January 23 from 15:23 to 15:51 UT in Photon Counting mode shows the presence of a dust scattering halo around the position of the Anomalous X-ray Pulsar 1E1547.0-5408. A bright ring with a radius of about 1 arcmin is clearly visible, but the observation is too short to detect expansion. Assuming that this ring is due to the bright burst detected on Jan 22 at 06:48:04 UT (Mereghetti et al. GCN 8841), and that the distance of 1E1547.0-5408 is 10 kpc, the distance inferred for the dust layer responsible for the scattering is about 7 kpc. Further observations to measure the time evolution of the dust scattering rings can provide tighter constraints. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8851 SUBJECT: Konus-Wind detection of very bright SGR-like burst on January 25, 2009 DATE: 09/01/25 14:26:02 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: A very bright short burst triggered Konus-Wind at 2009-01-25 T0=31417.781 s UT (08:43:37.781). The Konus-Wind light curve (strongly affected by pileup) of this burst is available at http://www.ioffe.ru/LEA/SGRs/090125_T31417/ The emission is seen at least to 400 keV. The source of the burst is in the south ecliptic hemisphere. Retrospectively this burst resembles the famous event 980618d from SGR 1627-41 (Mazets et al. 1999 ApJ, 519, L151): http://www.ioffe.rssi.ru/LEA/SGR/Catalog/Data/1627/980618d.htm Taking in account the ongoing bursting activity of the AXP/SGR 1E1547.0-5408 we suggest the burst originated from this source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8857 SUBJECT: AXP 1E1547.0-5408: RHESSI observations up to 400 keV DATE: 09/01/28 01:40:47 GMT FROM: Eric Bellm at UCB/SSL E. Bellm, D. M. Smith, and K. Hurley on behalf of the RHESSI team report: On January 22, 2009, RHESSI observed repeated outbursts from AXP 1E1547.0-5408 (Gronwall et al., GCN 8833). After a single ~2 second burst at 03:50:38 UT, a series of bursts was recorded from 05:14:03--05:26:51 UT. A second series was observed from 06:43:48--06:55:57 UT. The periods without observed emission are attributable to SAA passages and Earth occultation. The brightest burst was observed at 06:48:05 UT. This burst showed an initial spike with a peak count rate of 2.6E5 counts/s over a 10 ms interval and emission to 400 keV. The spike was followed by the pulsing tail (~2 s period) reported by Mereghetti et al. (GCN 8841) using INTEGRAL SPI-ACS. A previous burst at 06:45:13.54 UT may have been brighter, as its peak showed evidence of saturation. A one minute complex of bursts beginning at 05:17:40 UT showed emission to 250 keV. RHESSI observed a fast spike from the SGR at 05:18:32.45 UT. This event had an initial peak with a background-to-peak rise time of 12 ms and FWHM of 16 ms. A shoulder after the initial peak extended the total duration (T90) to 70 ms. This spike was also observed by INTEGRAL SPI-ACS. A lightcurve for this burst is available at http://ssl.berkeley.edu/ipn3/1E154/rhessi.pdf //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8858 SUBJECT: Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity DATE: 09/01/28 13:50:34 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov and T. Cline, on behalf of the Konus-Wind team, report: Since the renewal of bursting activity of the AXP/SGR 1E1547.0-5408 on January 22 (Gronwall et al., GCN 8833; Connaughton & Briggs, GCN 8835; von Kienlin & V. Connaughton, GCN 8838; Savchenko et al. GCN 8837; Terada et al., GCN 8845; Bellm et al., GCN 8857) Konus-Wind have seen 11 triggers from this source. The first trigger at 2009-01-22 T0=3554.882 s UT (00:59:14.882) contains many bursts and represent the cluster of bursts which started at ~T0-210s. The second trigger also contains several bursts. Remaining triggers contain single bright bursts. There is a data gap from 02:13 to 15:43 UT on Jan 22, 2009 which cannot be recovered. The following is a list of the Konus-Wind triggers with preliminary estimations of the bursts fluences and peak fluxes. The KW trigger times and corresponding Earth-crossing times are given. ------------------------------------------------------------------- # Date T0(KW) T0Earth Localized Fl** PF** UT UT by ------------------------------------------------------------------- 1* 20090122 00:59:14.882 00:59:18.550 GBM 8.0 8.0 2* 20090122 02:09:22.183 02:09:25.849 BAT 5.7 1.3 3 20090122 17:02:52.833 17:02:56.474 BAT 2.7 2.5 4 20090122 21:07:56.190 21:07:59.824 - 1.0 3.4 5 20090122 23:14:50.460 23:14:54.090 GBM 4.7 7.8 6 20090123 01:19:37.838 01:19:41.465 BAT,GBM 2.7 7.5 7 20090123 02:42:05.150 02:42:08.774 GBM 3.2 9.7 8 20090123 16:54:33.488 16:54:37.087 GBM 1.3 5.6 9 20090125 08:43:37.781 08:43:41.303 IBIS 250 300 10 20090125 23:00:32.802 23:00:36.294 IPN,GBM 7.6 19 11 20090126 04:48:01.917 04:48:05.397 GBM 1.6 5.7 ------------------------------------------------------------------ * - these triggers contain several bursts, in Table we give total fluence of all bursts and peak flux of the brightest burst ** - Fluence (20-200 keV) in units of 1e-6 erg/cm2 *** - Peak Flux (20-200 keV) on 4ms time scale in units of 1e-5 erg/cm2/s Some Abbreviations: BAT: Swift BAT GBM: Fermi GBM IBIS: Imager on Board the INTEGRAL Satellite IPN: Interplanetary Network The spectra of the most bursts are well fitted (in the 20-500 keV energy range) by power low with exponential cutoff model with Epeak values in the 25-35 keV range. Some bursts demonstrate strong spectral evolution. Some spectra can be well fitted by simple power law model. The burst #3 while having moderate fluence has a peculiar spectrum. It is well fitted by grbm model with alpha ~-1, Ep ~40, and beta ~-3.2 (cutoffpl model provides much worse chi2), the emission is seen up to 500 keV. The burst #9 (Golenetskii et al., GCN 8851) is the brightest burst detected by Konus-Wind from this AXP/SGR. It has the hardest spectrum with Epeak ~70 keV. Its duration (~400ms), energy output ~2.4x10^42 erg (for d=9 kpc), and peak luminosity ~2.9x10^43 erg/s are close to the characteristics of the famous event 980618a from SGR 1627-41 (dT~0.5 s, Q = 3x10^42 erg, L = 8x10^43 erg/s for d=5.8 kpc: see Mazets et al., ApJ, 519, L151 (1999)). There is no any sign of pulsating tail in both cases. The second burst in brightness (#10) has the second in hardness spectrum with Ep ~45 keV. Numerous short soft bursts most likely originated from this source were detected by Konus-Wind in the waiting mode. We thank Sandro Mereghetti for poiting our attention to the IBIS/ISGRI localization of the very bright SGR burst 090125 (T0=31417.781 s UT 08:43:37.781). We thank David Palmer for providing us with the information about BAT observations of the KW bursts. We also thank all IPN teams which provided us with the information about observations of the KW bursts by their instruments. [GCN OPS NOTE(28jan09): Per author's request, the "152" was replaced with "L151".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8859 SUBJECT: Suzaku ToO Observation of AXP 1E 1547.0-5408 DATE: 09/01/29 04:40:01 GMT FROM: Yujin E. Nakagawa at RIKEN Kazuhisa Mitsuda on behalf of Suzaku team reports: A Suzaku ToO observation of the currently active AXP 1E 1547.0-5408 (Gronwall et al. 2009, GCN Circ., 8833) is scheduled. It was started at 21:15:00 on January 28 2009 (UT) and will continue until 21:32:00 on 29 January 2008 (UT). All the Suzaku narrow field instruments (XIS and HXD: 0.2-600 keV energy range) will be on during the observation. The Suzaku observation will be coincident with the INTEGRAL observations during the periods from 21:37:00 on January 28 2009 (UT) to 03:42:34 on January 29 2009 (UT), and from 14:04:46 to 21:32:00 on January 29 2009 (UT). Further follow-up observations at other wavelengths are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8860 SUBJECT: IBAS Alert N. 5442 is not a GRB DATE: 09/01/29 14:41:11 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay), on behalf of the IBAS Localization Team reports: IBAS Alert N. 5442 is not due to a real GRB, but to a burst from the currently active AXP 1E 1547.0-5408. The burst origin was not automatically recognized due to wrong satellite attitude information. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8863 SUBJECT: Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29 DATE: 09/01/30 15:08:43 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov and T. Cline, on behalf of the Konus-Wind team, report: A very bright burst from the AXP/SGR 1E1547.0-5408 triggered Konus-Wind at 2009-01-29 T0=33427.224 s UT (09:17:07.224). This burst was localized by Fermi/GBM (trigger 254913432). Preliminary estimations yields a burst fluence of ~5.1x10^-5 erg/cm2, a peak flux on 2ms time scale of ~7.8x10^-4 erg/cm2/s (both in the 20-300 keV), and Ep ~95 keV for the time-integrated spectrum. So, it is the second burst in brightness detected by Konus-Wind from this AXP/SGR after the very bright burst 090125 (Golenetskii et al., GCN 8851, 8858). First two spectra of the burst (accumulated from T0 to T0+0.064s and from T0+0.064s to T0+0.128s) suffers from saturation and pileup effects and can not be accurately analyzed by the standard tools. The spectrum of the less intense part of the burst (accumulated from T0+0.128s to T0+0.256s) is well fitted (in the 20-1000 keV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.99(-0.39, +0.45), and Ep = 43.7 (-7.7, +5.2) keV (chi2 = 25.4/19 dof). Since the alpha is ~-1, this spectrum can be also well fitted by OTTB model with kT = 43.7(-3.7, +4.0) keV (chi2 = 25.4/20). There is a sign of high energy tail in the spectrum, so fitting by GRB model yields slightly better chi2 and: the low-energy photon index is alpha = -0.39(-0.73, +0.34), the high energy photon index beta = -3.65(-0.74, +0.34), the peak energy Ep = 45.6(-4.6, 3.6) keV (chi2 = 21.1/18 dof). All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this burst (affected by pileup in the most intense part) is available at http://www.ioffe.ru/LEA/SGRs/090129_T33427/ Another burst from the AXP/SGR 1E1547.0-5408 triggered Konus-Wind at 2009-01-29 T0=50794.800 s UT (14:06:34.800). This burst was imaged by IBIS/ISGRI and also observed by Fermi/GBM (trigger 254930799). As observed by Konus-Wind it had a fluence of ~8.4x10^-7 erg/cm2 and a peak flux on 4ms time scale of ~2.8x10^-5 erg/cm2/s (both in the 20-200 keV range). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8881 SUBJECT: ICSP VLF observation of the signatures of SGR/AXP 1E1547.0-5408 bursts DATE: 09/02/04 14:54:24 GMT FROM: Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci ICSP VLF observation of the signatures of SGR/AXP 1E1547.0-5408 bursts Sandip K. Chakrabarti (S. N. Bose Centre and ICSP), Sushanta K. Mondal (ICSP), Sudipta Sasmal (ICSP) and Debashis Bhowmick (ICSP) A number of recent satellite observations have reported the outbursts of anomalous X-Ray Soft gamma repeater AXP 1E1547.0-5408 which reportedly started from January 22nd, 2009 (GCN #8833, 8835, 8837, 8838). We looked at the ionospheric data of Indian Centre for Space Physics (ICSP) obtained by receiving Very Low Frequency (VLF) signal from the VTX station at 18.2KHz for the 22nd of January (IST), 2009 (21st Jan. 18:30 UT to 22nd Jan. 18:30 UT) using a Gyrator-II receiver. We found statistically significant signatures of short bursts which either suddenly amplified the signal or suddenly attenuated the signal. Each event lasted for a few seconds as the recombination time is usually longer than the burst duration. We observe 30 significant signatures out of which 9 were not reported by others and these events mostly took pace in late 21st January, 2009 (UT) before other satellite results were reported. However, the timings of the remaining 21 events match with the satellite observations. A list and the light curves of all the major events seen by us in the 22nd January (IST) can be found in http://www.bose.res.in/~chakraba/axpsgr.html. Since both the amplifications and the attenuations were seen, often one after the other, each event could tell us about the energy spectrum in each burst as the upper ionosphere would be primarily affected by soft-X-rays and the lower ionosphere would be primarily affected by the hard-X-rays. The highly tangential source illumination of the ionosphere as seen from ICSP (22d34m N, 88d21m E) was probably advantageous. We encourage other VLF observers to look into such signatures and particularly the latitude dependence. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8900 SUBJECT: Detailed lightcurves of ICSP VLF Observation of SGR/AXP 1E1547.0-5408 DATE: 09/02/11 05:01:57 GMT FROM: Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci. ICSP VLF observation of SGR/AXP 1E1547.0-5408 bursts on 22nd January, 2009 Sandip K. Chakrabarti (S. N. Bose Centre and ICSP), Sushanta K. Mondal (ICSP), Sudipta Sasmal (ICSP) and D. Bhowmick (ICSP) In a previous GCN (#8881) we reported that we were able to identify signatures of unusual activities in the ionosphere based on VLF data averaged over 10 points (5 seconds). After correcting the time stamps and using non-averaged data we are now in a position to claim that numerous ionospheric activities (fast rise and slow decay light curves over 10-20 seconds or more) have been observed on 22nd January, many of which match the activities reported in previous GCNs from FERMI/INTEGRAL/SUZAKU/RHESSI and other teams (e.g., GCNs 8833, 8835, 8837, 8838). Due to intrinsic problem of directional insensitivity and recombination time in lower ionosphe we found two problems (a) Begining of new activity before the earlier one decayed causing display of 'non-ideal' shape change, (b) influence of other active sources could be present. Interesting cases where many activities happened in close succession (as reported mainly by SUZAKU and HESSI) have been separated and they can be found in four PDF files (one2two.pdf, two2three.pdf, 426to533.pdf and eight2nine.pdf). Unlike one or two cases in our previous circular #8881 (based on smoothed data) attenuation events were not found when original data was used. These files are in http://www.bose.res.in/~chakraba/axpsgr2.html. In order to understand the response of the ionosphere by X-ray/gamma-ray activities better, we urge other VLF observers to report if they obtained any such effects. They must check if the object was over their sky during the active period. Prof. Sandip K. Chakrabarti Senior Professor and Head, Astrophysics and Cosmology S.N. Bose National Centre for Basic Sciences JD Block, Salt Lake, Kolkata 700098 INDIA Tel: 23355706 and In Charge, Academic Affairs Indian Centre for Space Physics Chalantika 43, Garia Station Road, Kolkata 700084 INDIA M: 9903120700 Tel: 24366003/24622153 -- Open WebMail Project (http://openwebmail.org) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8901 SUBJECT: SGR activity seen by BAT during ICSP Ionospheric Events DATE: 09/02/12 01:13:04 GMT FROM: David Palmer at LANL David Palmer, on behalf of the Swift-BAT team, reports: S.K Chakrabarti, et al. (GCN #8881) report disturbances in the ionosphere observed by ICSP as measured by 18.2 kHz radio propagation. Some of these were correlated with reported bursts from AXP 1E1547.0-5408 (== SGR J1550-5418) and it was suggested that the other disturbances indicated unreported activity. Swift-BAT has seen over 800 bursts from this source, but a complete catalog is still being prepared. However, the times of the ICSP events can be examined to see how reliably VLF measurements of ionospheric disturbances can determine SGR activity in a 'blind search'. Of the 9 ionospheric events in GCN #8881 which did not correspond to reported SGR events, all fortuitously occurred at times when the SGR was above the horizon as seen by BAT, and five occurred when the SGR was in BAT's Field of View. The BAT 15-100 keV count rate light curves were examined with 64 ms resolution within one minute of the times of these ICSP events to search for correlated SGR bursts. the results are given in the following table: Time of ICSP event Exposure (UT from GCN #8881) cm^2 Detection 2009-01-21T19:50:57 1413 None 2009-01-21T21:16:50 0 None 2009-01-21T21:35:01 1300 None 2009-01-21T23:19:56 1361 None 2009-01-21T23:56:07 0 Possibly real[1] 2009-01-22T00:32:32 0 None 2009-01-22T05:41:22 4364 Coincidence[2] 2009-01-22T05:56:02 4364 Coincidence[3] 2009-01-22T09:34:09 0 None [1] Double burst at T-10 seconds, peaking at 3 kcount/s. Due to the orientation of the spacecraft, the SGR could illuminate the back of the BAT detector only through the body of the Swift spacecraft, so this would correspond to a much more intense burst than the comparable count rate from a source in the FOV. If this is an SGR burst, it marks the earliest known detection during this episode. (Previous earliest was Fermi-GBM Trigger 254278434, at 2009-01-22T00:53:52.) [2] Strong burst at T+15 (~100kcounts/s), midsize burst (~20 kcount/s) at T+32, weaker bursts (<5 kcount/s) at T-42,T+8,T+11. [3] Weak burst (5k/s) at T-8 The 2009-01-21T23:56:07 disturbance [1] is the most compelling one for blind detection of activity. The non-detections by BAT on 2009-01-21 in those cases where the SGR location was in the FOV indicate that those ionospheric disturbances were unrelated to the SGR. The burst activity around the 2009-01-22T05:41:22 [2] and 2009-01-22T05:56:02 [3] disturbances is likely to be coincidental, considering the large amount of activity occurring around that time: during the 40 minute BAT observation from 5:37-6:17, there were 6 bursts comparable to or stronger than the 05:41:37 strong burst (which came after the ionospheric disturbance), and at least 32 bursts total seen by BAT. From this we conclude that ionospheric disturbances are not a reliable measure of SGR bursts in the absence of high energy confirmation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8910 SUBJECT: Swift Restored DATE: 09/02/19 18:11:26 GMT FROM: Michael Siegal at Swift/PSU As of UT 17:54:30, Swift is back in normal science operations. Any further BAT triggers should be considered valid. -Mike Siegel, Swift Observatory Duty Scientists //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8913 SUBJECT: Ongoing activity of AXP/SGR 1E1547.0-5408 DATE: 09/02/22 16:55:58 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov and T. Cline, on behalf of the Konus-Wind team, report: Two very bright SGR bursts triggered Konus-Wind at 2009-02-21 T0=55653.101 s UT (15:27:33.101) and 2009-02-22 T0=1694.689 s UT (00:28:14.689). The first was also detected by Fermi/GBM (trigger 256922856). The GBM location is consistent with the AXP/SGR 1E1547.0-5408 position. The Konus ecliptic latitude response indicates that the source of these bursts is in the south ecliptic hemisphere. So, we believe they originated from AXP/SGR 1E1547.0-5408. Preliminary estimations yields for the first burst a fluence of ~1.6x10^-5 erg/cm2, a peak flux on 2ms time scale of ~2.3x10^-4 erg/cm2/s (both in the 20-300 keV), and Ep ~50 keV for the time-integrated spectrum, and for the second burst a fluence of 4.3x10^-6 erg/cm2, a peak flux on 2ms time scale of ~1.4x10^-4 erg/cm2/s (both in the 20-300 keV), and Ep ~40 keV for the time-integrated spectrum. The Konus-Wind light curves of these bursts are available at http://www.ioffe.ru/LEA/SGRs/090221_T55653/ and http://www.ioffe.ru/LEA/SGRs/090222_T01694/ Since January 29 (Golenetskii et al., 8863) seven bright bursts from the AXP/SGR 1E1547.0-5408 have triggered Konus-Wind: ------------------------------------ Date T0, s UT ------------------------------------ 2009-02-03 8722.534 (02:25:22.534) 2009-02-03 70382.351 (19:33:02.351) 2009-02-04 73637.930 (20:27:17.930) 2009-02-12 43144.456 (11:59:04.456) 2009-02-14 70303.255 (19:31:43.255) 2009-02-21 55653.101 (15:27:33.101) 2009-02-22 01694.689 (00:28:14.689) ------------------------------------ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8915 SUBJECT: SGR J1550-5418 DATE: 09/02/26 00:34:30 GMT FROM: Chryssa Kouveliotou at MSFC SGR J1550-5418 (former AXP 1E 1547.0-5408): list of triggers from the Fermi Gamma-ray Burst Monitor (GBM)   C. Kouveliotou (NASA-MSFC), A. von Kienlin (MPE), G. Fishman (NASA-MSFC),  V. Connaughton (UAH), A. van der Horst (NASA-MSFC/ORAU), and N. Bhat (UAH), report on behalf of the Fermi GBM Team: During the current active period of SGR J1550-5418 which began on 22 January 2009 (GCNs 8833, 8835), the Fermi Gamma-ray Burst Monitor (GBM) has triggered on 117 discrete bursts through 24 February, of which 15 were extremely intense. Additionally, a multitude of untriggered events have also been recorded over the same period.  The source is still active, but with a decreased rate of triggers to ~twice per day, with exceptionally intense bursts occurring about once per week.  A list of all Fermi GBM triggers from SGR J1550-5418 in the time interval above, with the particularly intense events noted by an asterisk, is given at: http://gammaray.nsstc.nasa.gov/gbm/science/magnetars. NOTE: our trigger times are not necessarily the same as event peak times, depending on the event durations, which range from milliseconds to 1-2 sec. Many of the intense bursts from SGR J1550-5418 are expected to produce measurable ionospheric disturbances, as recorded by observations of VLF radio propagation (GCNs 8881, 8900).  Observations of these disturbances over different elevation angles could provide unique insight into the low energy (<2 keV) emission from this SGR during bursts, as well as the total ionizing X-ray fluence deposited in the upper atmosphere.  Correlations of these outbursts with data from detectors on other spacecraft are also encouraged.  Analyses of the duration, peak fluxes, fluences and spectral characteristics of these events from GBM data are in progress. Finally, we would like to stress that the source bursting behavior clearly classifies it as a Soft Gamma Repeater, contrary to the initial classification as an Anomalous X-ray Pulsar (AXP) by Camilo et al. (2007, ApJL 666, 93), who only used the persistent source spectrum and pulsation period for a tentative classification. Similar to the Swift team (GCN 8901) therefore, we will call the source out as SGR J1550-5418 in the future. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8928 SUBJECT: Konus-RF catches first GRB and SGR bursts DATE: 09/03/04 15:01:46 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, V. Il'inskii, P. Oleynik, M. Ulanov, D. Svinkin, on behalf of the Konus-RF and Konus-Wind teams, report: At 07:25:57 UT on February 27, 2009 the KONUS-RF gamma-ray spectrometer detected its first gamma-ray burst, GRB 090227A (Fermi/GBM trigger 257412359 / 090227310: Bissaldi GCN 8917). That day at 13:43:36 UT the instrument detected a bright short soft burst from the AXP/SGR 1E1547.0-5408. Both bursts also triggered Konus-Wind. The Konus-RF gamma-ray spectrometer is an instrument of the CORONAS-PHOTON solar space observatory that was launched on January 30, 2009 into a low-Earth low-eccentricity, high-inclination orbit (altitude 547-592 km, inclination 82.5 deg). CORONAS-PHOTON is a 3-axis stabilized, Sun-pointing spacecraft. Konus-RF has been successfully operating since February 19. The Konus-RF experiment is aimed at studying of temporal and spectral characteristics of solar flares, gamma-ray bursts, and SGR bursts in a wide energy range from 10 keV to 10 MeV. It consists of two identical omnidirectional detectors one of which points toward the Sun thereby observing the solar hemisphere, and the other observes the antisolar hemisphere. Thus, the instrument provides continuous monitoring of the unocculted sky. However, the usable exposure time is severely limited by passage through the radiation belts at high latitudes and the South Atlantic Anomaly. Each detector employs NaI(Tl) crystal, 127 mm in diameter and 76.2 mm in height, supplied with a beryllium entrance window. The Konus-RF instrument is an advanced modification of the Russian-American Konus-Wind spectrometer. More details can be found at http://www.astro.mephi.ru/coronos-photon_conusrf_e.htm The Konus-RF and Konus-Wind light curves of the SGR burst 090227 are available at http://www.ioffe.ru/LEA/SGRs/090227_T49414/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8950 SUBJECT: ATCA observation of SGR J1550-5418 DATE: 09/03/09 05:34:44 GMT FROM: Aquib Moin at CIRA/ATNF Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope National Facility), Steven Tingay (Curtin Institute of Radio Astronomy), Chris Phillips (Australia Telescope National Facility), Gregory Taylor (University of New Mexico), Mark Wieringa (Australia Telescope National Facility) and Ralph Martin (Perth Observatory) report: We observed the SWIFT-BAT position of recently re-activated Soft Gamma-ray Repeater source SGR J1550-5418 or AXP 1E1547-5408 (GCN 8833) at 4.800 and 4.928 GHz with the Australia Telescope Compact Array (ATCA) between 01:00:00 UT and 22:00:00 UT on February 21/22, 2009. The ATCA observations of SGR J1550-5418 were conducted immediately before the VLBI ToO observations of the source with the Australian Long Baseline Array (LBA). We clearly detected a radio source at the position of the SGR J1550-5418 at the frequencies of 4.800 & 4.928 GHz. The data at these frequencies were combined to make an image and the radio flux density at the source position found out to be 68.3 +/- 4.3 mJy/beam. The Australia Telescope Compact Array (/ Parkes telescope / Mopra telescope / Long Baseline Array) is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. See the 4.800 & 4.928 GHz combined image at: http://cira.ivec.org/dokuwiki/doku.php/sgr_j1550-5418/sgr_j1550-5418_field_image //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9014 SUBJECT: A bright burst from AXP 1E 1547.0-5408/SGR J1550-5418 DATE: 09/03/23 02:25:59 GMT FROM: Marco Feroci at IASF/INAF E. Del Monte, Y. Evangelista, M. Feroci, I. Donnarumma, F. Lazzarotto, L. Pacciani, P. Soffitta, E. Costa, I. Lapshov, M. Rapisarda (INAF/IASF Rome), A. Giuliani, A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan), A. Pellizzoni, M. Pilia (OA Cagliari), S. Vercellone (INAF/IASF Palermo), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, V. Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini (INAF/IASF Rome), G. Barbiellini, F. Longo, E. Moretti (INFN Trieste), P. Picozza, A. Morselli (INFN Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), and P. Giommi, C. Pittori, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, report: "A bright burst from AXP 1E 1547.0-5408 / SGR J1550-5418 was triggered and imaged by SuperAGILE on 22 March 2009, at 22:39:16 UT. The event had a duration of about 250 ms, with a multi-peak structure. The peak flux on the 10 ms timescale was approximately 3.6e-5 erg/cm2/s in the 20-60 keV energy range, based on the raw assumption of a Crab-like energy spectrum. The latest reported bursting activity from this source dates back to 2009, Feb 24th (Kouveliotou et al., GCN #8915)." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9025 SUBJECT: SGR J1550-5418: two Fermi GBM triggers on March 22 DATE: 09/03/24 04:34:35 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU) and C. Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM team: "The Fermi Gamma-Ray Burst Monitor (GBM) has triggered on two bursts from SGR J1550-5418 on March 22. The first occurred at 18:56:23.75 (trigger 259440985 / 090322789) and the second at 22:39:15.75 UT (trigger 259454357 / 090322944). The latter burst was very bright, and also detected by SuperAGILE (GCN 9014). Both bursts were independently detected by INTEGRAL SPI-ACS. These are the first GBM triggers after the second active period of SGR J1550-5418 that ended on February 24, 2009. A complete list of the GBM triggers from this SGR can be found at: http://gammaray.nsstc.nasa.gov/gbm/science/magnetars." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9072 SUBJECT: GRB DATE: 09/04/01 15:51:31 GMT FROM: Ascension Camero-Arranz at NASA VP62/FECYT Subject: GRB 090331: Fermi GBM detection A. Camero-Arranz (NASA; FECYT) and C. Wilson-Hodge (NASA/MSFC), report on behalf of the Fermi GBM Team: "At 16:20:20.39 UT on 03 31 09, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 090331 ( trigger 260209222/ 090331681). The on- ground calculated location, using the Fermi GBM trigger data, is RA = 212.38, Dec = -0.51 (J2000 degrees, equivalent to J2000 14h 09m, -00d 31' ), with a statistical uncertainty of 6.7 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 40 degrees. Since the source is weak, the time-averaged spectrum is poorly constrained." Subject: GRB 090331: Fermi GBM detection A. Camero-Arranz (NASA; FECYT) and C. Wilson-Hodge (NASA/MSFC), report on behalf of the Fermi GBM Team: "At 16:20:20.39 UT on 03 31 09, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 090331 ( trigger 260209222/ 090331681). The on- ground calculated location, using the Fermi GBM trigger data, is RA = 212.38, Dec = -0.51 (J2000 degrees, equivalent to J2000 14h 09m, -00d 31' ), with a statistical uncertainty of 6.7 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 40 degrees. Since the source is weak, the time-averaged spectrum is poorly constrained." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9112 SUBJECT: Fermi GBM Detection of a weak source DATE: 09/04/08 21:49:48 GMT FROM: Vandiver Chaplin at UAH/Fermi-GBM V.Chaplin (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “On 07 April 2009 at 18:43:55.25 UT, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located a weak source (trigger 260822637 / 090407781). The most likely nature of the source is a weak GRB. The GBM lightcurve consists of a weak pulse of about 3 seconds starting from T0-3, and appears to only have emission between 10-100keV. Since the source is very weak, it is not possible to find a reliable on-ground calculated location and to perform any spectral analysis." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9315 SUBJECT: Refined analysis of ICSP VLF observation of SGR J1550-5418 bursts on 22nd January, 2009 DATE: 09/05/01 12:42:06 GMT FROM: Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci. Refined analysis of ICSP VLF observation of SGR J1550-5418 bursts on 22nd January, 2009 Sandip K. Chakrabarti (S. N. Bose Centre and ICSP), Sushanta K. Mondal (ICSP), Sudipta Sasmal (ICSP) and D. Bhowmick (ICSP) In continuation of our previous reports (GCN #8881 and GCN #8900) we present our refined analysis of VLF observations by ICSP. We identified as many as 73 satellite events (e.g., GCNs 8833, 8835, 8837, 8838) which could be associated with ionospheric features observed by ICSP VLF receiver at Kolkata. Some of these events last only tens of seconds which others last longer. Very often successive events occur even before the earlier one decayed, making identifications more difficult. Two images (4450.jpg and 8950.jpg) of the comparison with satellite detections are in the http://www.bose.res.in/~chakraba/axpsgr3.html. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9444 SUBJECT: Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet? DATE: 09/05/30 14:22:52 GMT FROM: Krzysztof Z. Stanek at Ohio State U J. L. Prieto, L. C. Watson & K. Z. Stanek (Ohio State University) In their study of supernova hosts using SDSS data (Prieto, Stanek & Beacom 2008, ApJ, 673, 999), the broad-lined SN Ic 2007bg at z=0.034 (Quimby et al. 2007, CBET 927; Harutyunyan et al. 2007, CBET 948; Soderberg & Immler 2007, ATEL 1142), was identified as a good candidate for an off-axis GRB. The likely host of SN 2007bg is an extremely low-luminosity galaxy with M_B ~ -12, one of the least-luminous supernova hosts of any kind ever observed. Since such a low-luminosity host is almost certain to be very metal poor (~1/20 solar; e.g., Lee et al. 2006, ApJ, 647, 970), this broad-line SN Ic supernova is a very good candidate for association with an off-axis GRB (e.g., Stanek et al. 2006, AcA, 56, 333). Given that, Prieto, Stanek & Beacom (2007, GCN 6618) encouraged follow-up observations of SN 2007bg to look for an off-axis GRB jet. Following up on their suggestion, we have analyzed some of the publicly available radio data obtained at the VLA at several epochs in several bands (Proposal #AS0887; PI A. Soderberg), and have detected a very strong radio source at the position of SN 2007bg: UT | days after SN disc. | nu (GHz) | flux (mJy) | error (mJy) | Luminosity density (erg/s/Hz) Apr. 19.2, 2007 3.1 8.46 0.15 0.04 3.6e27 Aug. 18.9, 2007 124.7 8.46 0.58 0.04 1.4e28 Feb. 25.2, 2008 315.0 8.46 1.77 0.10 4.4e28 This makes SN 2007bg one of the strongest radio supernovae ever observed, in fact >4 times more luminous at approx. 1 year after explosion compared with SN 2003L (Soderberg et al. 2005, ApJ, 621, 908) and SN 2003bg (Soderberg et al. 2006, ApJ, 651, 1005), which were among the most luminous SN Ib/c observed in radio, see more details and figures at http://www.astronomy.ohio-state.edu/~prieto/sn2007bg/ In fact, such strong radio emission a year after the explosion makes SN 2007bg an even better candidate for an off-axis GRB (e.g., Paczynski 2001, AcA, 51, 1), given that the only other broad-line SNe Ic ever observed in low metallicity enviroments have been associated with GRBs (Stanek et al. 2006, AcA, 56, 333; Modjaz et al. 2008, AJ, 135, 1136). Further follow-up observations at all wavelengths are greatly encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9485 SUBJECT: GRB DATE: 09/06/03 15:51:34 GMT FROM: Solen Balman at METU S. Balman (METU), M. Parmaksizoglu (TUG) Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.) I. Bikmaev, N. Sakhibullin (KSU/AST) R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), report: We observed the field of GRB090529 (trigger=353540, Sakamato et al. 2009 GCN Circ. 9430, also GCN Circ. 9431-9436,9448,9449,9457) with the Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) on 30 May starting at 00:09:01.86 UT about 9.94 hours (0.414 d) after the burst using the TFOSC CCD (burst detected at 14:12:35 UT with Swift Burst Alert Telescope (BAT)). We obtained one 900 sec exposure using the R band filter (Bessell filter). We found the afterglow candidate at the location designated by the Swift XRT position given by Osborne et al. 2009 GCN Circ. 9433. We performed PSF photometry using DAOPHOT within MIDAS software on the 13.3 by 13.3 arcmin field around the afterglow candidate. We calibrated the R band magnitude using the same USNO-B1 reference star noted by Kann et al. 2009 GCN Circ. 9436. The GRB090529 afterglow candidate is detected at R = 21.2+/-0.2 mag. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9499 SUBJECT: Discovery of a new soft gamma repeater source, SGR 0418+5729 DATE: 09/06/09 04:24:27 GMT FROM: Alexander van der Horst at NASA/MSFC A. J. van der Horst, V. Connaughton, C. Kouveliotou, M. S. Briggs, and W. S. Paciesas report for the Fermi/GBM team, V. Pal'shin, S. Golenetskii, R. Aptekar, D. Frederiks, E. Mazets, P. Oleynik, D. Svinkin, M. Ulanov, and K. Hurley report for the Konus-RF team, J. R. Cummings, D. Palmer, and N. Gehrels report for the Swift-BAT team "The Fermi Gamma-Ray Burst Monitor (GBM) has triggered on two SGR-like bursts on June 5 at 20:40:48.88 (trigger 265927250 / 090605862) and 21:01:35.06 UT (trigger 265928497 / 090605876). Their on-ground calculated locations, using the Fermi GBM trigger data, are: - RA, Dec (J2000) = 70.0, +55.6 (equivalent to 4h40m, +55d35'), with a 1-sigma statistical uncertainty of 4.8 degrees, and - RA, Dec (J2000) = 60.5, +55.4 (equivalent to 4h02m, +55d22'), with a 1-sigma statistical uncertainty of 6.0 degrees, respectively. For both triggers there is additionally a systematic error which is currently estimated to be 2 to 3 degrees. The angles from the Fermi LAT boresight are 81 and 66 degrees, respectively. The time-averaged GBM spectra of both triggers are best fit by a power law with a high-energy exponential cutoff. The indices are -0.26 +/- 0.39 and -0.38 +/- 0.76, and the cutoff energies, parametrized as Epeak, are 36.0 +/- 2.4 and 22.9 +/- 3.3, for the first and second trigger, respectively. The first event was a single pulse of 0.03 seconds, while the second trigger was double-peaked with a duration of 0.09 seconds. The first burst was also seen by Konus-RF which was triggered at 2009-06-05 74448.88972 s UT (20:40:48.890). We have triangulated this burst to a Konus-RF - GBM annulus centered at RA, Dec (J2000) = 84.314 (05h 37m 15s), -6.669 (-6d 40' 07"), with a radius of 66.544 +/- 4.812 deg (3 sigma). This annulus is consistent with the two on-ground calculated GBM locations. The nearby, confirmed SGR source, SGR 0501+4518 (RA, Dec (J2000) = 75.265, +45.272) is ~12 degrees away from the centerline of this annulus and is, therefore, excluded as the origin of these two new emissions. Swift BAT triggered on the first GBM event (BAT trigger #354188). No source was found onboard. After the alert through the IPN network, the event data were analyzed on the ground, and a low-significance source was found at a position consistent with the GBM position and IPN annulus. The position is RA, Dec (J2000) = 64.606, +57.489, equivalent to RA(J2000) = 04h 18m 25s Dec(J2000) = +57d 29' 16'' with an uncertainty of 4 arcmin (radius, statistical+systematic, 90% containment). As seen in BAT, the burst T90 was 3.5 +/- 1.0 ms. There was no emission seen above 100 keV. We have also used the BAT light curve to obtain a BAT-GBM annulus centered at RA, Dec (J2000) = 129.334 (08h 37m 20s), +0.546 (+0d 32' 45"), with a radius of 76.480 +/- 1.452 deg (3 sigma). The annulus contains the Swift localization and is consistent with both GBM locations. The second GBM event was seen very weakly in BAT, but did not cause a rate trigger, so no further data are available. A map of the GBM, BAT locations, and the Konus-RF - GBM and BAT-GBM annuli can be obtained at: http://gammaray.nsstc.nasa.gov/gbm/science/magnetars. The Galactic coordinates of the Swift location are L, B = 148.00, 5.07 deg, placing the source on the galactic plane. We tentatively propose this as a new soft gamma repeater source, SGR 0418+5729." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9502 SUBJECT: RXTE Discovery of Pulsations from SGR 0418+5729 DATE: 09/06/10 15:43:29 GMT FROM: Ersin Gogus at Sabanci U/Turkey Ersin Gogus (Sabanci Univ.), Chryssa Kouveliotou (NASA/NSSTC), Peter M. Woods (Dynetics) report on behalf of a larger collaboration: Following the Fermi GBM/Konus/Swift detection of bursts from the new Soft Gamma Repeater SGR 0418+5729 (van der Horst et al. 2009, GCN #9499) we triggered our SGR ToO Program with RXTE. A 6.8 ks RXTE observation started on 2009 June 10, 03:42:56 UT. We detect a strong, coherent pulsations from the new SGR (2-10 keV) in the PCA GoodXenon mode data at 0.110152(2) Hz, corresponding to a spin period of 9.0783(1) sec. The pulse morphology is complex showing two asymmetric maxima per cycle. We note that there is no previously known X-ray source in the RXTE field of view with such periodicity. The detected coherent pulsations likely indicate the spin period of the newly discovered, burst-active SGR. We thank the project scientist Jean Swank, and the RXTE planner, Divya Pereira for the prompt scheduling of the RXTE observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9506 SUBJECT: SGR 0418+5729 Fermi/GBM Detection of Pulsations DATE: 09/06/12 15:39:18 GMT FROM: Zsolt Bagoly at Eotvos U. Zsolt Bagoly (Eotvos Univ.), Peter Veres (Eotvos Univ., Bolyai Univ.), Istvan Horvath (Bolyai Univ.), Lajos Balazs (Konkoly Observatory) and Attila Meszaros (Charles Univ.) report: Following the Fermi GBM/Konus/Swift detection of bursts from the new SGR 0418+5729 (van der Horst et al. 2009, GCN #9499), and the RXTE discovery of the of 9.0783 sec period pulsations in the 2-10 keV band (E. Gogus et al. 2009, GCN #9502) we analysed the June 5 20:40:48.88 (trigger 265927250 / 090605862) observation of the SGR by the Fermi GBM. Using the GBM gamma data from the 3 triggered NaI detectors and the 2 BGOs we have identified 14 short (shorter than 16ms) pulses, with intensity >4 sigma above the noise. 5 groups were identified among these pulses (times are relative to the trigger): Group 1: 54.976 s, 181.968 s, 245.408 s, 263.776 s Group 2: 104.960 s, 223.040 s, 232.080 s Group 3: 131.008 s, 203.616 s, 257.712 s Group 4: 98.992 s, 135.104 s Group 5: 69.984 s, 164.368 s The in-group time differences for Groups 1-4 correspond to multiples of the 9.0783 sec pulsation period (with <6% error). The probability of such random fluctuation is lower than 5e-4. Group 5 appears to be noise. The phase difference relative to the trigger is 0.044 +/- 0.011 for the Group 1 pulses and 0.564 +/- 0.004 for the Group 2 pulses, showing almost a symmetrical behaviour. The Group 3 and 4 phase differences are 0.409 +/- 0.022 and 0.893 +/- 0.011 respectively. This could be the indication of a more complex high energy pulse morphology similarly to the RXTE observed one (E. Gogus et al. 2009, GCN #9502) . This analysis encourages further follow-up observations at high energy. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9664 SUBJECT: Swift satellite anomaly DATE: 09/07/14 20:36:03 GMT FROM: Neil Gehrels at GSFC The Swift observatory is currently experiencing an anomaly, and normal science operations have been temporarily suspended. Data on the onboard solid state recorder (SSR) were found to be corrupted starting at 1532UT on July 12. The spacecraft is still pointing as commanded. Good data are returned when the downlink is through TDRSS and when real-time data are sent to the Malindi ground station during a pass. It appears that the problem is in the writing or storage of data on the SSR. The anomaly is being worked by a group including the operations team at Penn State, the Swift project at Goddard and the General Dynamics engineering team in Gilbert, Arizona. The first step will be to fully characterize the problem, followed by efforts to restore operations of the SSR. During this time, Swift will observe targets that were being viewed prior to the anomaly. Swift will not slew to new TOOs or new GRBs. BAT will continue to detect new GRBs and transients, and will telemeter the usual messages through TDRSS to the ground for distribution by the GCN. XRT and UVOT continue to observe, but almost none of the science data are being successfully transmitted to the ground. Ground-based follow-up of BAT GRBs is strongly encouraged. More information will follow as we learn more. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9669 SUBJECT: Swift problem fixed DATE: 09/07/15 21:47:14 GMT FROM: Neil Gehrels at GSFC The anomaly with the Swift on-board solid state recorder has been resolved and the mission is back to autonomous slewing for GRBs. Normal observing and TOO requests will be enabled tomorrow (July 16) morning. The anomaly was resolved by sending a "stop all transfers" command to the recorder on July 15 at ~1500UT. This essentially reset the input and output interfaces. Data dumps following the commanding indicate that the recorder is working normally again. An investigation on the root cause is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9922 SUBJECT: Swift-BAT temporarily off-line for a few days DATE: 09/09/17 18:06:43 GMT FROM: Scott Barthelmy at NASA/GSFC Scott Barthelmy and Neil Gehrels, on behalf of the Swift Team: The Swift-BAT instrument experienced a partial flight software crash around ~10:30 UT on 17 Sep 2009. All the temperatures, voltages, currents, etc indicate that the instrument is fine -- only the science collection portion of the flight software has stopped working. The fundamental problem has been identified and a fix to the software is being implemented. The portion that runs the observing program continues to run, so the spacecraft continues to point and collect NFI data on the planned targets. It will take several days to get the BAT flight software running again; and during that time there will be no BAT triggers on new GRBs. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9928 SUBJECT: Swift returns to normal operations DATE: 09/09/22 16:47:31 GMT FROM: Scott Barthelmy at NASA/GSFC Scott Barthelmy and Neil Gehrels, on behalf of the Swift Team: As of 16:30 UT 22-Sep-2009, Swift is back to normal operations. BAT has been recovered, triggering enabled, and slewing to new bursts has been enabled. XRT and UVOT are also taking data on planned targets are and ready for new burst targets. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10096 SUBJECT: A mistake in testing a new fucntion in Swift DATE: 09/10/28 17:42:15 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) on behalf of the Swift team: At 17:28:08 UT (28 Oct 09) an XRT_Position Notice was distributed (TrigNum 20117). This notice was a result of a test that the Swift team was conducting to test a new function within the spacecraft. I had the swift_blocked2world filter enabled in GCN, and as such the notice should have been blocked. The other notices were blocked, but this one leaked through. I apologise for the confusion. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10167 SUBJECT: GRB09111: Swift XRT refined analysis DATE: 09/11/13 14:19:06 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano, B. Sbarufatti (INAF-IASF PA), H. A. Krimm (CRESST/GSFC/USRA) and D. M. Palmer (LANL) report on behalf of the Swift-XRT team: The INTEGRAL burst GRB091111 (Gotz et al. GCN Circ. 10159) has been observed by Swift on 2009 11 12 with a 5 ks ToO started at 19:00 UT (trigger 020120). We have analysed 5.4 ks of XRT data in PC mode, from 100361 s to 115.3 ks after the INTEGRAL trigger. An X-ray source is detected at RA, Dec 137.82427, -45.92541 which is equivalent to: RA(J2000) = 09h 11m 17.82s Dec(J2000) = -45d 55' 31.5" with an uncertainty of 5.1 arcseconds (radius, 90% containment). The light curve is probably decaying but more data are needed to estimate the decay slope. A spectrum formed from the PC mode data (30 counts within a circular region of 15 pixel radius) can be fitted with an absorbed power-law with a photon spectral index of 2.5 (+5, -3.4) The best-fitting absorption column is < 5 x 10^22 cm-2, consistent with the Galactic value of 6.2 x 10^21 cm-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 7.0 x 10^-11 (2.7 x 10^-10) erg cm^-2 count^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020120. At the time of GRB 091111, the Swift/BAT was active, sensitive and pointing such that the burst was in the BAT field of view with 25% mask coding. There is no count rate increase detected in any of the four BAT energy bands This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10229 SUBJECT: Short X-ray Transient Detection by MAXI/GSC DATE: 09/12/02 16:24:59 GMT FROM: Nobuyuki Kawai at Tokyo Tech M. Nakajima, S. Miyoshi (Nihon U.), M. Morii, K. Sugimori, N. Kawai (Tokyo Tech), H. Negoro, H. Ozawa, R. Ishiwata (Nihon U.), M. Suzuki, M. Matsuoka, K. Kawasaki, S. Ueno, H. Tomida, M. Ishikawa (JAXA), S. Eguchi, Y. Ueda, N. Isobe, K. Hiroi (Kyoto U.), S. Nakahira, A. Yoshida, K. Yamaoka (AGU), T. Mihara, M. Kohama, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto (RIKEN), H. Tsunemi, M. Kimura (Osaka U.), A. Daikyuji (Miyazaki U.) report on behalf of the MAXI team: At the scan transit centered at UT 2009-12-01T21:48:36, MAXI/GSC detected an X-ray source, which was detectable at least for 20 seconds within the 67 seconds triangular transit response of MAXI/GSC. With the current statistics we cannot distinguish whether the source was constant over the scan transit. Assuming that the source flux was constant over the transit, the source location is determined as (R.A., Dec)=(118.6 deg, 16.6 deg) = (07 54 24, +16 36 36) (J2000) with a systematic uncertainty of 0.4 degrees. If the source was highly variable, as is the case for a GRB/XRF, the uncertainty along the scan direction becomes large, as we cannot fit the light curve to the triangular transit response. Without assumptions on the source constancy, we obtain a rectangular error box with the following corners: (R.A., Dec)=(116.27 deg, 14.59 deg) = (07 45 04.80, +14 35 24.0) (J2000) (R.A., Dec)=(116.96 deg, 14.14 deg) = (07 47 50.40, +14 08 24.0) (J2000) (R.A., Dec)=(120.22 deg, 19.33 deg) = (08 00 52.80, +19 19 48.0) (J2000) (R.A., Dec)=(120.96 deg, 18.95 deg) = (08 03 50.40, +18 57 00.0) (J2000) The preliminary flux (2-10 keV) of the source was 120 mCrab. There was no significant detection at the transit location in the previous and following orbits (92 min before or after the detection) with an upper limit of 20 mCrab. There is no known bright X-ray source at the detected position. At the galactic coordinates (l,b)=(204.6, 21.2), the source can be either a Galactic object (e.g. flare stars, compact objects) or an extragalactic object (e.g. GRB/XRF, AGN, SN). Follow-up observations are encouraged. MAXI is currently in the commissioning phase. Note: Since the nature of the source is unknown, this message is cross-posted to ATEL and GCN. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10251 SUBJECT: A small revision to the GRB-naming convention DATE: 09/12/07 22:23:42 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), N. Gehrels (GSFC), W. Paciesas (UAH), C. Kouveliotou (MSFC) J. McEnery (GSFC), J. Chiang (SLAC) K. Hurley (UCB), N. Kawai (Tokyo Tech), V. Pal'shin (IOFFE), D. Frederiks (IOFFE), M. Tashiro (Saitama U.), K. Yamaoka (Aoyama Gakuin U.), S. Mereghetti (INAF/IASF Milano), M. Feroci (INAF/IASF Rome), E. Del Monte (INAF/IASF Rome), M. Marisaldi (INAF/IASF Bologna), S.K. Chakrabarti (SNBNCBS and ICSP, Kolkata, India) report: This is to announce that the GRB-producing missions have agreed to a slight change in the way GRBs are named. Starting 01 Jan 2010 the first GRB (on a given day) that is published will automatically be given the designation of the "A" burst. In the past the first burst published in a given day was not given a letter (i.e. just plain GRB YYMMDD), and was only given the "A" designation if a second burst was detected on that day (and also published, aka the "B" burst). And any later publications on the first burst were then given the "A" suffix. This new naming scheme follows the method used for supernova; the first SN of the year is always given the "A" designation, the second "B" and so on. The motivation for this change to the naming convention is to avoid the confusion in the literature when the initial citations of the "first" burst start out with no letter and then later citations have the "A" suffix. This should also help with the authors of the first burst to get the correct designation. This revised method of naming bursts will start on 01 January 2010. And to reiterate the rest of the method of naming GRBs (this part is staying the same): GRBs are named in the order of puplication, not the time-order of their detections. And "publishing" a burst is defined by a GCN Circular, ATEL, IAU Circular, or even a journal publication. To be equally clear, a GCN Notice does not constitute a publication of the burst. The important distinction being that a Circular, etc, involves off-line human-in-the-loop analysis of the event to determine if it a real GRB (or something non-GRB), whereas a Notice is automated and contains non-GRB events. The humans make the determination and give the name "GRB YYMMDDA". These aspects of how and when a burst is named are staying the same. The only change is to automatically give the "A" designation to the first burst, even if there is no second burst that day. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10252 SUBJECT: Short X-ray Transient, RIMOTS optical upper limits DATE: 09/12/08 02:09:31 GMT FROM: Arata Daikyuji at Miyazaki U A.Daikyuji, K.Noda, E.Sonoda, H.Hayasi, K.Kono, N.Ohmori, Y.Nishioka, M.Yamauchi (University of Miyazaki) We have observed a part of the error region of Short X-ray Transient detected by MAXI (GCN 10229, M. Nakajima et al.) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 20:22:04 UT. We have compared our data of 30 sec exposures with the USNO-A2.0 and GSC catalog. There is no new source at the reported position. The corners of observed region are as follows: (R.A., Dec)=(118.29 deg, 16.44 deg) = (07 53 11.00, +16 26 17.7) (J2000) (R.A., Dec)=(118.30 deg, 16.92 deg) = (07 53 12.70, +16 55 31.9) (J2000) (R.A., Dec)=(118.88 deg, 16.91 deg) = (07 55 30.80, +16 54 56.3) (J2000) (R.A., Dec)=(118.87 deg, 16.43 deg) = (07 55 29.30, +16 25 50.4) (J2000) The upper limits are as follows: ------------------------------------------------------------- Start(UT) End(UT) Num. of frames Limit (mag.) -------------------------------------------------------------- 20:43:14 20:43:44 1 14.0 20:22:04 21:00:21 30 16.6 --------------------------------------------------------------- //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10316 SUBJECT: Swift/BAT Detects an Outburst from XTE J1901+014 DATE: 10/01/08 15:19:40 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA), P. Romano, S. Vercellone (INAF-IASF Palermo), S. D. Barthelmy (GSFC), W. Baumgartner (CRESST/GSFC/UMBC), J. Cummings (CRESST/GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), C. B. Markwardt (CRESST/GSFC/UMD), D. Palmer (LANL), T. Sakamoto (CRESTT/GSFC/UMBC), G. Skinner (CRESST/GSFC/UMD), M. Stamatikos (OSU/GSFC), J. Tueller (GSFC), T. Ukwatta (GSFC/GWU) At 00:58:50.58 UT on 2010-Jan-08 (MJD 55204), Swift/BAT triggered on a rapid outburst from XTE J1901+014. The trigger was a 128-second image trigger and detectable emission lasted from T-150 sec to at least T+250 sec, when the spacecraft moved away from the field due to a pre-planned slew. The time-averaged spectrum from T-137.5 to T+263.9 sec is best fit by a simple power-law model. The photon power law index of the time-averaged spectrum is 5.22 +- 0.51. The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10-6 erg/cm2. This corresponds to 0.056 ± 0.010 ct/s/cm2 or 250 mCrab in the 15-50 keV band. Due to an observing constraint (proximity to the sun), no Swift XRT or UVOT observations will be possible until 2010-Feb-16. This is the second time Swift/BAT has triggered on XTE J1901+014. The first was on 2006-June-06 at 10:17:18.76 for a weaker flare. The time-averaged spectrum of the 2006 flare from T+0.0 to T+33.1 sec was best fit by a simple power-law model. The photon power law index of the time-averaged spectrum was 4.32 +- 1.94 and the fluence in the 15-150 keV band was 1.1 +- 0.7 x 10-7 erg/cm2. The flux in a 1984-second observation beginning at 10:17:18 averaged 0.068 ± 0.048 ct/s/cm2 (31 mCrab, 15-50 keV). XTE J1901+014 is normally barely detectable in the BAT hard X-ray transient monitor at ~2.5 mCrab. It has shown signs of increased, but variable, activity since about 2009-Dec-03. This source was discovered in 2002 (Remillard and Smith, ATel #88) and is known for having rapid, intense variations in its X-ray flux (e.g. Smith et al, ATel #1268). The true nature of the source is still in question. Optical photometry of the field suggests a low mass companion and the source may be the first low-mass fast X-ray transient (Karasev, Lutovinov & Burenin, 2008, Astron. Lett., 34, 753). This recent trigger tells us that XTE J1901+014 has again become active, so further observations are encouraged. Note that the trigger number in the recent GCN Circular (Palmer, Cummings and Sakamoto, GCN Circular #10315) is incorrect. The subject line should have referred to Swift/BAT trigger #382159. Trigger #382180 was correctly identified onboard as XTE J1901+014. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10359 SUBJECT: Short X-ray Transient detected by MAXI/GSC DATE: 10/02/03 17:07:00 GMT FROM: Nobuyuki Kawai at Tokyo Tech M. Suzuki (JAXA), H. Negoro (Nihon U.), M. Morii, K. Sugimori, N.Kawai (Tokyo Tech), M. Matsuoka, K. Kawasaki, S. Ueno, H. Tomida, M. Ishikawa (JAXA), T. Mihara, M. Kohama, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto (RIKEN), A. Yoshida, K. Yamaoka, S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), M. Nakajima, S. Miyoshi, H. Ozawa, R. Ishiwata,(Nihon U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.) report on behalf of the MAXI team: At the scan transit centered at UT 2010-02-02T17:14:52, MAXI/GSC detected a transient X-ray source, which was present at least for 15 seconds within the 110 seconds triangular transit response of MAXI/GSC. The nominal location of the source, assuming that the source flux was constant over the transit (which probably was not), is determined as (R.A., Dec)=(261.05 deg, -32.94 deg) = (17 24 12, -32 56 24) (J2000) with a rectangular 90% statistical error box with the following corners: (R.A., Dec)= (261.11 deg, -33.27 deg) = (17 24 26, -33 16 12)(J2000) (R.A., Dec)= (260.75 deg, -33.23 deg) = (17 23 00, -33 13 48)(J2000) (R.A., Dec)= (261.00 deg, -32.67 deg) = (17 24 00, -32 40 12)(J2000) (R.A., Dec)= (261.36 deg, -32.72 deg) = (17 25 26, -32 43 12)(J2000) The systematic uncertainties are calibrated using bright sources found in the same scan, and therefore, are much smaller. If the source was only temporarily bright during the scan, which is well expected for the case of a GRB/XRF or an X-ray burst, uncertainty along the scan direction becomes larger, as we cannot fit the light curve to the triangular transit response. Without assumptions on the source constancy, we obtain a rectangular error box with the following corners: (R.A., Dec)= (260.33 deg, -34.11 deg) = (17 21 19, -34 06 36)(J2000) (R.A., Dec)= (260.81 deg, -34.15 deg) = (17 23 14, -34 09 00)(J2000) (R.A., Dec)= (261.89 deg, -31.74 deg) = (17 27 34, -31 44 24)(J2000) (R.A., Dec)= (261.43 deg, -31.67 deg) = (17 25 43, -31 40 12)(J2000) The nominal flux (4-10 keV) of the source was about 120 mCrab if the source was constant over the transit. The flux could be 300 mCrab or higher if the emission was present only for 15 seconds within the transit. There was no significant detection at this location in the previous and following orbits (92 min before or after the detection) with an upper limit of 20 mCrab. There is no known bright X-ray binary source at the detected position. At the galactic coordinates (l,b)=(354.1, 1.7), the source is likely to be Galactic, although extragalactic origin cannot be ruled out. With a very preliminary spectral analysis, the energy spectrum can be modeled by a highly absorbed (NH>1e23 cm-2) blackbody (kT~1.5 keV), suggestive of a type-1 X-ray burst at a large distance. The scan light curve and the source location will be posted at the MAXI web site http://maxi.riken.jp at the news section. Note: Since the nature of the source is unknown, this message is cross-posted to ATel and GCN. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10446 SUBJECT: GRB DATE: 10/02/22 18:00:16 GMT FROM: Janos Kelemen at Konkoly Obs/Hungary GRB 100213B R band observations J. Kelemen (kelemen at konkoly.hu) on behalf of the GRB OT observing program at the Konkoly Observatory. On 15 february 2010 19:56:20 UT we observed the field of GRB 100213B detected by Swift (trigger #412220; Vetere et al., GCN 10412) with a 60/90 cm Schmidt telescope located at the Mountain Station of the Konkoly Observatory using R filter. The total exposure of the coadded images were 2700 s. We examined both the XRT position and the position reported D. Malesani et al. GCN 10413. No new object brighter than 21.3 +/- 0.2 was found. Time Mag Error. Flag. [s] [R] [1-sigma] ------------------------------------- 161866 21.30 0.2 Upper Limit ------------------------------------- This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10483 SUBJECT: IBAS Alert 5992 is not a GRB, but XTE J1855-026 DATE: 10/03/14 20:17:33 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti, A. Paizis, (IASF- Milano), D.Gotz (CES-Saclay), E. Bozzo, C. Ferrigno, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: at 19:04:25 UT of March 14, IBAS triggered on a source at coordinates RA: 283.871338 [degrees] DEC: -2.609381 [degrees] these are consistent with the position of the high mass X-ray binary XTE J1855-026. The event that caused the trigger is visible only in the low energy range 15-40 keV and lasts several tens of seconds. We conclude that the IBAS Alert is not due to a GRB but it is most likely due to this galactic source. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10528 SUBJECT: Swift-BAT refined analysis of the probable new SGR 1833-0832 DATE: 10/03/19 22:55:16 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), J. M. Gelbord (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT trigger #416485 (Gelbord, et al., GCN Circ. 10526). The BAT ground-calculated position is RA, Dec = 278.446, -8.533 deg, which is RA(J2000) = 18h 33m 47.1s Dec(J2000) = -08d 32' 00.2" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 87%. The mask-weighted light curve shows two resolved peaks with a total duration of ~16 millisec. T90 (15-350 keV) is 0.012 +- 0.009 sec (estimated error including systematics). The time-averaged spectrum from T+0.000 to T+0.016 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -1.02 +- 1.35, and Epeak of 38.2 +- 5.0 keV (chi squared 43.5 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.49 sec in the 15-150 keV band is 0.2 +- 0.1 ph/cm2/sec. Similarly, a blackbody fit yields kT= 10.0 +-1.2 keV (chi squared 43.8 for 57 d.o.f). A fit to a simple power law gives a photon index of 2.58 +- 0.23 (chi squared 74.2 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/416485/BA/ Given (a) the low galactic lattitude (0.01 deg), (b) the short duration of the event, and (c) the spectral softness (Epeak=38.2 and photon index of -1.02), we believe this to be an event from a new probable SGR which we are calling SGR 1833-0832. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10529 SUBJECT: Swift-XRT refined position of the probable new SGR 1833-0832 DATE: 10/03/20 02:07:00 GMT FROM: Jonathan Gelbord at PSU/Swift J.M. Gelbord (PSU) and L. Vetere (PSU) report on behalf of the Swift-XRT team: We have analysed 959 s of XRT data for BAT trigger #416485 (Gelbord et al. GCN Circ. 10526), from 80 s to 1.3 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The refined XRT position for this burst is RA, Dec 278.435, -8.519 which is equivalent to RA(J2000) = 18h 33m 44.4s Dec(J2000) = -08d 31m 08.4s with an uncertainty of 5.3 arcsec (radius, 90% confidence). This position may be improved as more data are received. We note that this position is 3.5 arcsec from the XRT position and 63.5 arcsec from the BAT position reported by Gelbord et al. (GCN Circ. 10526). At this time we cannot confirm whether the source is decaying. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10530 SUBJECT: Probable SGR 1833-0832: Enhanced Swift-XRT position DATE: 10/03/20 07:42:38 GMT FROM: Phil Evans at U of Leicester P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Using 5452 s of XRT Photon Counting mode data and 8 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 278.43520, -8.51880 which is equivalent to: RA (J2000): 18 33 44.45 Dec (J2000): -08 31 07.7 with an uncertainty of 1.6 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions; all XRT products for this event are available at http://www.swift.ac.uk/xrt_products/00416485. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10531 SUBJECT: Probable SGR 1833-0832: Swift-XRT refined analysis DATE: 10/03/20 13:37:15 GMT FROM: Jonathan Gelbord at PSU/Swift J.M. Gelbord (PSU) and L. Vetere (PSU) report on behalf of the Swift-XRT team: We have analysed 22.5 ks of XRT data for SGR 1833-0832 (Gelbord et al. GCN Circ. 10526), from 80 s to 52.8 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 10530). The light curve is consistent with a SGR but not a GRB, as the present data exhibit little variability and do not decay. When the light curve is modelled with a power-law, the best-fitting alpha = 0.05 (+0.19,-0.17). The mean aperture-corrected count rate is 0.031 (+/-0.002) counts per second. A spectrum formed from these data can be fitted with an absorbed power-law with a photon spectral index of 3.21 (+0.69, -0.64). The best-fitting absorption column is 1.38 (+0.35, -0.30) x 10^23 cm^-2, in excess of the Galactic value of 1.7 x 10^22 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 1.1 x 10^-10 (4.7 x 10^-9) erg cm^-2 count^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00416485. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10534 SUBJECT: Discovery of the Spin Period of SGR 1833-0832 DATE: 10/03/20 16:22:48 GMT FROM: Ersin Gogus at Sabanci U/Turkey --001485f726fed3fb5704823d9a84 Content-Type: text/plain; charset=ISO-8859-1 Ersin Gogus (Sabanci Univ), Tod Strohmayer (NASA/GSFC), Chryssa Kouveliotou (NASA/MSFC), Peter Woods (Dynetics) Discovery of the Spin Period of SGR 1833-0832 Following the Swift detection of a burst from the new Soft Gamma Repeater SGR 1833-0832 (Gelbord, J. et al. 2010, GCN #10526) we triggered our SGR ToO Program with RXTE. A 1.3 ks RXTE observation started on 2010 March 19, 21:49:52UT. We detect coherent pulsations from the new SGR in the 2-20 keV PCA data at 0.1321 Hz, corresponding to a spin period of 7.57 sec. We then performed timing analysis on 22.5 ks Swift/XRT data in PC mode and confirmed the period detection as 7.5654(1) s. We note that there is no previously known X-ray source in the RXTE field of view with such periodicity. The detected coherent pulsations likely indicate the spin period of the newly discovered, burst-active SGR. We thank the RXTE planner, Divya Pereira for the prompt scheduling of the RXTE observations and Scott Barthelmy, Jonathan Gelbord and Neil Gehrels from the Swift team for valuable and prompt information exchange on this new source. --001485f726fed3fb5704823d9a84 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Ersin Gogus (Sabanci Univ), Tod Strohmayer (NASA/GSFC), Chryssa Kouveliotou=
(NASA/MSFC), Peter Woods (Dynetics)

Discovery of the Spin Period= of SGR 1833-0832

Following the Swift detection of a burst from the = new Soft Gamma Repeater
SGR 1833-0832 (Gelbord, J. et al. 2010, GCN #10526) we triggered our SGR ToO Program with RXTE. A 1.3 ks RXTE observation started on 2010 March 19= ,
21:49:52UT. We detect coherent pulsations from the new SGR in the 2-2= 0 keV
PCA data at 0.1321 Hz, corresponding to a spin period of 7.57 sec. We then =
performed timing analysis on 22.5 ks Swift/XRT data in PC mode and conf= irmed
the period detection as 7.5654(1) s. We note that there is no pre= viously
known X-ray source in the RXTE field of view with such periodicity.
The= detected coherent pulsations likely indicate the spin period of
the ne= wly discovered, burst-active SGR.

We thank the RXTE planner, Divya P= ereira for the prompt scheduling of the
RXTE observations and Scott Barthelmy, Jonathan Gelbord and Neil Gehrels from the Swift team for valuable and prompt information exchange on this =
new source.
--001485f726fed3fb5704823d9a84-- //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10535 SUBJECT: Discovery of the Spin Period of SGR 1833-0832 DATE: 10/03/20 16:31:28 GMT FROM: Paolo Esposito at INAF-IASF,Milano Paolo Esposito, Gian Luca Israel, Luigi Stella, Nanda Rea, Andrea Tiengo report: We analysed 22.5 ks of XRT data in Photon Counting (PC) mode of the new soft gamma-ray repeater candidate SGR 1833-0832 (Gelbord et al. GCN Circ. 10526, 10531). The data were barycentered using the X-ray position reported in Evans et al. (GCN Circ. 10530). We detect strong pulsations from the X-ray source in the 2-10 keV band at 7.5653(5) sec. The background subtracted pulsed fraction, defined as the semiamplitude of sinusoidal modulation divided by the mean source count rate, is 64+/-4%. The pulse is highly significant (the probability of such a signal to appear by chance in the search, taking into account the 32768 trials, is about 5E-18) and is not present in the background data. We caution however that this value is close to three times the XRT PC frame time, 2.507 s. At the link below a plot of the source and background data folded at our best fit period and at 3*2.507 s can be seen. Further observations are needed to confirm this period. http://www.iasf-milano.inaf.it/~paoloesp/sgr1833.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10536 SUBJECT: SGR 1833-0832 is pulsed at 7.56 seconds DATE: 10/03/20 16:32:56 GMT FROM: David Palmer at LANL David Palmer (LANL) and J. M. Gelbord (PSU), on behalf of the Swift Team, reports: Analysis of the XRT data from T+80s to T+15 hours from the new probable SGR 1833-0832 (Gelbord et al. GCN Circ. 10526) shows strong pulsations at an unbarycentered period of 7.5646(3) s. The detection of pulsations, combined with the other SGR-like features of this event, strongly indicate that this object is a new discovery of a Soft Gamma Repeater, and should be monitored for further bursts. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10537 SUBJECT: SGR 1833-0832 is pulsed at 7.56 seconds DATE: 10/03/20 16:35:44 GMT FROM: David Palmer at LANL David Palmer (LANL) and J. M. Gelbord (PSU), on behalf of the Swift Team, reports: Analysis of the XRT data from T+80s to T+15 hours from the new probable SGR 1833-0832 (Gelbord et al. GCN Circ. 10526) shows strong pulsations at an unbarycentered period of 7.5646(3) s. The detection of pulsations, combined with the other SGR-like features of this event, strongly indicate that this object is a new discovery of a Soft Gamma Repeater, and should be monitored for further bursts. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10538 SUBJECT: SGR 1833-0832: Archival Chandra Observations DATE: 10/03/20 19:45:21 GMT FROM: Ersin Gogus at Sabanci U/Turkey Ersin Gogus (Sabanci Univ.), reports on behalf of a larger team The field covering the newly discovered Soft Gamma Repeater SGR 1833-0832 (Gelbord, J. et al. 2010, GCN #10526) was observed with Chandra ACIS-S starting on 2009 February 13, 10:50:20 UT for 8 ks. There is no point source detected within the best Swift XRT error circle (Evans et al. 2010, GCN #10530). Employing spectral parameters reported by Gelbord et al. (2010, GCN #10530), we obtain a 2-sigma upper limit to the unabsorbed flux as 3.4E-13 erg/cm2/s. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10540 SUBJECT: SGR 1833-0832: Swift/UVOT Upper Limits DATE: 10/03/22 22:08:21 GMT FROM: Frank Marshall at GSFC F.E. Marshall (NASA/GSFC) and J.M. Gelbord (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of SGR 1833-0832 71 s after the BAT trigger (Gelbord et al., GCN Circ. 10526). No optical afterglow consistent with the XRT position (Evans and Goad, GCN_Circ. 10529) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposures and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 71 220 147 >20.6 u_FC 283 533 246 >20.5 white 71 57748 1793 >22.3 v 612 69706 3549 >21.4 b 539 57397 3660 >21.3 u 283 75812 5479 >22.3 w1 4479 75666 6430 >21.8 m2 5710 74760 4446 >22.5 w2 5300 68903 3050 >22.3 The values quoted above are not corrected for the Galactic extinction due to the very large reddening in the direction of the source (Schlegel et al. 1998). The large X-ray column density to the source found with the Swift/XRT (Gelbord and Vetere, GCN Circ. 10531) also indicates very large optical extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10549 SUBJECT: Fermi/GBM and Swift/BAT detection of a burst from SGR 1806-20 DATE: 10/03/29 13:36:33 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAHuntsville), David Palmer (Los Alamos National Laboratory), Chryssa Kouveliotou (NASA/Marshall Space Flight Center) and Scott Barthelmy (NASA/Goddard Space Flight Center) report on behalf of a larger collaboration: "The Fermi/Gamma-Ray Burst Monitor (GBM) triggered on 2010 March 26 at 20:48:59.86 UT on the SGR-like event 100326 (trigger 291329341 / 100326867). The on-ground calculated location, using the GBM trigger data, is RA = 265.93, DEC = -22.09 (J2000 degrees, equivalent to 17h 43.7m, -22d 5.4'), with an uncertainty of 4.5 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The GBM location includes the position of at least two SGR sources: the confirmed SGR 1806-20 and the candidate SGR 1801-23. The GBM burst light curve shows one pulse with a duration of about 100 ms (25-50 keV). The angle from the Fermi LAT boresight is 45 degrees. The time-averaged spectrum from T0-0.064s to T0+0.048 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -0.40 (+/-0.31) and the cutoff energy, parameterized as Epeak, is 33.50 (+/- 1.94) keV (CSTAT 468 for 508 d.o.f.). The event fluence (8-1000 keV) in this time interval is (7.88 +/- 0.39)E-07 erg/cm^2. The 32-msec peak photon flux measured starting from T0+0 s in the 10-1000 keV band is 16.38 +/- 0.78 ph/s/cm^2. The Swift/Burst Alert Telescope (BAT) also detected GBM100326.867 but the image significance was not above threshold. BAT located the event to within 1 arcminute of SGR 1806-20, which we conclude is the origin of the burst emission. This is the first burst that BAT has detected from this source since since 2010, February 10, and the largest since 2007, November 9. The spectral analysis results presented above are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10551 SUBJECT: Fermi GBM detection of four Solar Flares DATE: 10/03/30 10:16:23 GMT FROM: Sheila McBreen at MPE S. McBreen (UCD/MPE) reports on behalf of the Fermi GBM Team: "On 27 March 2010 the Fermi Gamma-Ray Burst Monitor triggered and located four solar flares. The events are listed below. Trigcat Trigger UTC ---------------------------------------------- GBM 100327.218 291359679 05:14:37.43 GBM 100327.330 291369350 07:55:48.66 GBM 100327.405 291375797 09:43:15.44 GBM 100327.424 291377472 10:11:10.04 In at least one case there is soft emission visible ~50 seconds before the trigger time." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10552 SUBJECT: Short X-ray Transient detected by MAXI/GSC DATE: 10/03/30 10:51:35 GMT FROM: Atsumasa Yoshida at Aoyama Gakuin U H. Tomida, M. Matsuoka, K. Kawasaki, S. Ueno, M. Suzuki, M. Ishikawa (JAXA), M. Morii, K. Sugimori, N. Kawai (Tokyo Tech), T. Mihara, M.Kohama, M. Sugizaki, Y.E. Nakagawa, T. Yamamoto, T. Saotome (RIKEN), A. Yoshida, K. Yamaoka, S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), H. Negoro, M. Nakajima, S. Miyoshi, H. Ozawa,R. Ishiwata (Nihon U.), Y. Ueda, N. Isobe, S. Eguchi,K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), A. Uzawa,T. Matsumura, K. Yamazaki (Chuo U.), on behalf of the MAXI team At the scan transit centered at UT 2010-03-27T17:08:15,MAXI/GSC detected a transient X-ray source. Assuming constant flux over the transit, the source location is determined as (R.A., Dec) = (346.03 deg, 42.90 deg) = (23 04 07, 42 54 00) (J2000) we obtain a rectangular error box with the following corners: (R.A., Dec) = (+346.11 deg, +43.42 deg) = (23 04 25, +43 25 25)(J2000) (R.A., Dec) = (+345.53 deg, +43.21 deg) = (23 02 06, +43 12 48)(J2000) (R.A., Dec) = (+346.10 deg, +42.34 deg) = (23 04 24, +42 20 27)(J2000) (R.A., Dec) = (+346.68 deg, +42.54 deg) = (23 06 44, +42 32 26)(J2000) The preliminary flux (4-10keV) of the source is 110 mCrab. The source was not detected in 10-20keV band. There was no significant detection at the transit location in the previous and following orbits (92min before and after the detection) with an upper limit of 20mCrab. There is no known bright source at the detected position. Note: Since the nature of the source is unknown, this message is cross-posted to ATel and GCN. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10561 SUBJECT: Swift detection of LS V +44 17 DATE: 10/04/01 19:51:03 GMT FROM: David Palmer at LANL G. Stratta (ASDC), W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB), P. A. Curran (UCL-MSSL), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), W.B Landsman (GSFC), J. Mao (INAF-OAB), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU), R. L. C. Starling (U Leicester) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team: At 18:34:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 418109. Swift slewed to the location at the end of the trigger image interval. The BAT on-board calculated location is RA, Dec 70.262, +44.512 which is RA(J2000) = 04h 41m 03s Dec(J2000) = +44d 30' 44" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger (30 minute duration). The position is consistent with the known Be X-ray pulsar LS V +44 17, which was recently reported to be active (Morii et al, ATEL #2527). BAT has been detecting this source with marginal significance over the past few days, with the first detection (~60 mCrab) on 2010 March 29 at 21:39 UT. The XRT began observing the field at 19:08:39.4 UT, 2069.0 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 70.2497, +44.5297 which is equivalent to: RA(J2000) = 04h 41m 00.07s Dec(J2000) = +44d 31' 46.9" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 71 arcseconds from the BAT onboard position, within the BAT error circle. XRT position is consistent with LS V +44 17. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.60e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 2080 seconds after the BAT trigger. LS V +44 17 is bright at the XRT position and compromised by coincidence loss at a level which is uncorrectable. The SIMBAD magnitude for the source is V = 10.7, which is consistent with the UVOT image although more quantitative statements cannot be made. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10571 SUBJECT: Master-Net observations on the Swift trigger on LS V +44 17 DATE: 10/04/03 05:54:22 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zemnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok Irkutsk State University MASTER robotic telescope (MASTER-Net: http://observ.pereplet.ru, 2x400 mm, FOV=2x4 square degrees) located at Ural was responted to the trigger 418109 (Swift Bat alert, Stratt et al, GCN CIRC 10561) 19 sec after Notice time and 1820 s after the trigger time. MASTER took a finding chart synchronous exposure of 180 seconds with the two filters starting 1820 seconds after the BAT trigger. Unfortunatelly the optical star LS V+44 17 are saturated. The message may be cited. mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10573 SUBJECT: IBAS Alert n. 5995: not a GRB DATE: 10/04/03 19:07:40 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti, on behalf of the IBAS Localization Team report: the IBAS trigger n.5995 is not due to a GRB, but to the galactic source 1A0535+26 that was not automatically recognized due to inaccurate attitude information //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10574 SUBJECT: IBAS Alert n. 5996: not a GRB DATE: 10/04/03 19:50:26 GMT FROM: Diego Gotz at CEA D.Gotz, on behalf of the IBAS Localization Team report: like for IBAS trigger n. 5995, the IBAS trigger n.5996 is not due to a GRB, but to the galactic transient 1A0535+26, currently in outburst, that was not automatically recognized due to inaccurate attitude information. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10575 SUBJECT: MASTER observations on the Swift second trigger on LS V +44 17 DATE: 10/04/04 14:49:54 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zemnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok Irkutsk State University MASTER robotic telescope (MASTER-Net: http://observ.pereplet.ru, 2x400 mm, FOV=2x4 square degrees) located at Ural was responted to the trigger 418178 (Swift Bat alert, GRB_TIME: 20:33:14.32 UT) 25 sec after Notice time and 101 s after the trigger time. MASTER took a finding chart synchronous exposure of 30 seconds with the two telescopes starting 101 seconds after the BAT trigger. Fortunately optical star LS V+44 17 (9m) are not saturated. The message may be cited. mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10576 SUBJECT: INTEGRAL Alert n. 5995: MASTER-Net optical observations DATE: 10/04/04 15:26:04 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Kuvshinov, E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zemnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok Irkutsk State University Two MASTER robotic telescopes (MASTER-Net: http://observ.pereplet.ru) located at Vostryakovo (Moscow) and Tunka-Baykal was responted to the GRB 100403A (Integral alert 5995) 16 sec after Notice time and 35 s after the GRB time and 36 sec after Notice time and 55 s after the GRB time. Baykal weather is bad. Moscow weather is good. The Moscow result is: T-T_grb Exp m_lim Band 36 30s 17 Unfiltered The optical star HDE 245770 (~9m V) not saturated (companion of the X-ray pulsar A0535+26). It is interesting that both last INTEGRAL and Swift BAT alerts (GCN 10561, GCN 10573) are the result activity of the X-ray Pulsars with Be stars ( A0535+26 and LS V +44 17). By the way the X-ray pulasar A0535+26 is the NS with high magnetic field ~ 10^14 Gs (see very old paper Lipunov 1982, Soviet Astronomy, vol. 26, 537 or monograph: V.M. Lipunov, "Astrophysics of Neutron Stars", Springer-Verlag, Berlin, New-York, 1992). The message may be cited. mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10580 SUBJECT: Spin down rate and inferred dipole magnetic field of the new soft gamma-ray repeater SGR 1833-0832 DATE: 10/04/13 11:25:11 GMT FROM: Paolo Esposito at INAF-IASF,Milano P. Esposito (INAF-IASF Milano), G. L. Israel (INAF-O.A.Roma), M. Burgay (INAF-O.A.Cagliari), A. Possenti (INAF-O.A.Cagliari), D. Gotz (Irfu/SAp/CEA Saclay), N. Rea (CSIC-ICE Barcelona), S. Mereghetti (INAF-IASF Mi), A. Tiengo (INAF-IASF Mi), L. Stella (INAF-0.A.Roma), R. Turolla (U. Padua), S. Zane (MSSL/UCL) on behalf of a larger collaboration report: We observed the new soft gamma-ray repeater SGR 1833-0832 with XMM-Newton on 2010 March 23 (for about 22 ks) and on 2010 April 02 (for about 21 ks). By merging these data sets with those collected since the discovery of the source (GCN #10526) with RossiXTE and Swift, we were able to refine the period measurement reported in ATEL #2494 (see also ATEL #2493), also including in the phase-coherent timing solution a first period derivative component. According to our preliminary analysis the period and first period derivative of SGR 1833-0832 are: P= 7.565406(2) s and Pdot= 7.4(2) x 10^-12 s/s (1 sigma uncertainties; epoch 55274.0 MJD). Under the standard assumption that the neutron star slows down because of magnetic braking, we infer a dipole magnetic field of B = 2.4(3) x 10^14 G for a neutron star with radius of 10 km and mass of 1.4 solar masses, confirming the SGR as a new magnetar candidate. We will monitor the source both with XMM-Newton and Swift until the end of the current observability window (about end of April 2010). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10722 SUBJECT: An SGR-like burst from the magnetar 1E 1841-04.5 in Kes 73 DATE: 10/05/06 15:30:01 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), W.B Landsman (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 14:37:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located a short soft burst (trigger=421262) consistent with the location of the SNR Kes 73. Because this source was identified on board, it did not reach an automatic merit sufficient to cause a slew. The BAT on-board calculated location is RA, Dec 280.331, -4.921 which is RA(J2000) = 18h 41m 19s Dec(J2000) = -04d 55' 15" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single high bin at the 64 ms timescale, with an effective count rate of 4000 count/s 0.1 s after the nominal trigger time. The count rate during the 16 ms trigger interval averaged 12000 counts/s. When it was realized that this SNR contains a known magnetar AXP, and that this burst is consistent with Soft Gamma Repeater activity, we manually upgraded this target to ensure slewing. The XRT began observing the field at 15:09:15.9 UT, 1891.3 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 280.33059, -4.93731 which is equivalent to: RA(J2000) = 18h 41m 19.34s Dec(J2000) = -04d 56' 14.3" with an uncertainty of 4.4 arcseconds (radius, 90% containment), which is 3.2 arcseconds from the location of 1E 1841-04.5 (AKA PSR J1841-0456). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.57e+22 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 1895 seconds after the BAT trigger. The full 2.7'x2'7 sub-image has not been received and the partial image does not cover the XRT error circle. The 8'x8' region for the list of sources generated on-board confirms a known optical source within the XRT circle. The preliminary UVOT position is RA, Dec 280.33001, -4.93763 which is RA(J2000) = 18h 41m 19.20s Dec(J2000) = -04d 56' 15.5" with an estimated uncertainty of 1.1 arcsec (radius, 90% confidence, statistical + systematic). The white magnitude is 17.98 +- 0.35 No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10777 SUBJECT: Update to the configuration of the Fermi-LAT onboard GRB search DATE: 10/05/19 00:54:02 GMT FROM: Julie McEnery at NASA/GSFC Julie McEnery (GSFC), Gregg Thayer (SLAC), J. J. Russell (SLAC), Sylvia Zhu (GSFC) and Nicola Omodei (Stanford) report on behalf of the Fermi-LAT collaboration. On May 14, the Fermi- LAT team made a significant update to the configuration of the GRB search algorithm onboard the LAT. There are two search modes in the onboard algorithm: a) one that searches solely within the LAT data for spatial and temporal clusters of events and b) another that seeds a search based on the position and time of a GBM detected burst. The recent changes affect the GBM seeded case. For most of the mission the configuration of the onboard algorithm had a very low threshold for the GBM seeded window, as a diagnostic test on the algorithm performance. This meant that if even 1 event was observed within 10 deg radius of the GBM seed position then the LAT onboard flight software would trigger and enter a localization and refinement stage (essentially always triggering if the GBM position was in the LAT FoV). The localization and refinement stage lasts for 600 seconds, during which time no further triggers are allowed. We applied a filter on the ground before sending public GCN notices to filter out the large number of false triggers. The updated configuration performs a LAT search on a GBM seeded position at 2, 5, 10, 20, 30, 60, 90, and 150s after the GBM trigger. The threshold is applied onboard so that the LAT remains in trigger mode unless and until a significant number of events are seen that are consistent with the seeded position. This provides a capability to generate a LAT trigger for GRB where the high energy emission is significantly delayed with respect to the GBM detection. This behaviour has been seen from several GRB detected at high energies. To explore the false trigger rate, we ran the new configuration on 80,000 test positions. This resulted in a predicted false trigger rate of 0.33/year. To explore the ability of the new configuration to detect GRB, we ran it on data containing known LAT bursts. This resulted in triggers of 5 out of the first 13 LAT detected bursts (080916C, 081024B, 090510, 090902B, 090926). Previously, the LAT had sent out only one onboard-generated notice (090510). We thus expect the new configuration to provide onboard detections of 3-5 GRB/year, with localizations in the range 0.1 to 0.5 degrees. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10809 SUBJECT: Test of new capella2 version of GCN GRB DATE: 10/05/27 21:44:17 GMT FROM: Scott Barthelmy at NASA/GSFC test //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10810 SUBJECT: Test of new capella2 version of GCN GRB DATE: 10/05/27 21:47:48 GMT FROM: Scott Barthelmy at NASA/GSFC test //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10811 SUBJECT: Test of new capella2 version of GCN GRB DATE: 10/05/27 21:50:32 GMT FROM: Scott Barthelmy at NASA/GSFC test //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10823 SUBJECT: Swift detection of outburst from the SFXT IGR J18410-0535 DATE: 10/06/05 18:08:50 GMT FROM: David Palmer at LANL M. De Pasquale (UCL-MSSL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA), R. L. C. Starling (U Leicester) and L. Vetere (PSU) report on behalf of the Swift Team: At 17:23:30 UT, the Swift Burst Alert Telescope (BAT) detected increased flux from the Supergiant Fast X-Ray Transient IGR J18410-0535. Swift slewed to the source immediately after its detection. The BAT on-board calculated location is RA, Dec 280.267, -5.615 which is RA(J2000) = 18h 41m 04s Dec(J2000) = -05d 36' 53" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty), consistent with the known source location. As is typical for long image detections, the immediately available light curve shows no obvious activity. The XRT began observing the field at 17:51:50.5 UT, 1700 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 280.25128, -5.59666 which is equivalent to: RA(J2000) = 18h 41m 0.40s Dec(J2000) = -05d 35' 46.5" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This is consistent with the identification of this source as IGR J18410-0535. The position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.59e+22 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 1705 seconds after the BAT trigger. No credible optical transient has been found in the initial data products. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10957 SUBJECT: Swift/UVOT observations DATE: 10/07/14 12:38:05 GMT FROM: Massimiliano de Pasquale at MSSL-UCL M. De Pasquale (MSSL-UCL) and V. D'Elia (ASDC) on behalf of the Swift/UVOT team report: Swift/UVOT began settled observations of the INTEGRAL burst GRB100713A (Mereghetti et al., GCN 10951) 6247s after the trigger. At the position of the X-ray counterpart (D'Elia et al., GCN 10952), we do not detect any optical afterglow in the exposures in UVOT filters down to the following 3 sigma upper limits. Filter T_start (s) T_stop (s) Exp (s) Mag upper limit v 6403 6603 197 >19.6 wh 6247 12351 518 >21.8 b 11065 11965 880 >21.4 u 10152 11059 885 >20.7 uvw1 6813 6963 148 >19.8 uvm2 6608 6808 197 >19.6 The values quoted above are calculated using the UVOT photometric system (Poole et al 2008, MNRAS, 383, 627) and are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11132 SUBJECT: IBAS Alert n. 6057 is not due to a GRB DATE: 10/08/22 01:44:41 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay) and C. Ferrigno (ISDC Versoix) on behalf of the IBAS localisation team report: IBAS Alert n. 6057 is not due to a real GRB, but to an outburst of XTE J1701-407 lasting about 100 s. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11205 SUBJECT: GRB10901A: Optical observations at IAO DATE: 10/09/04 13:33:16 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe(IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 100901A (Immler et al., GCN 11159) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. Our observations started on 2010-09-02 13:22:45 UT (~1.0 day after the burst) and 2010-09-03 15:24:41 UT (~2.1 day after the burs). We detected the previously reported afterglow (Immler et al., GCN 11159; Guidorzi et al., GCN 11160; Kuroda et al., GCN 11172; Kuroda et al., GCN 11189; Ukawatta et al., GCN 11198) in all the three bands. Photometric results of the OT are listed below. We used SDSS catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err ---------------------------------------------------------------------- 1.04604 14:40:28 1560.0 19.49 0.04 18.86 0.04 18.25 0.05 1.08548 15:37:16 1560.0 19.59 0.04 18.93 0.04 18.41 0.06 1.14442 17:02:08 1500.0 19.64 0.05 19.11 0.04 18.50 0.07 2.13035 16:41:52 4020.0 20.71 0.08 19.96 0.06 20.04 0.17 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11212 SUBJECT: GRB10901A: Murikabushi telescope observation at 3 days after the burst DATE: 10/09/05 13:46:08 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe(IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 100901A (Immler et al., GCN 11159) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2010-09-04 17:11:19 UT (~3.15 day after the burst). We detected the previously reported afterglow (Immler et al., GCN 11159; Guidorzi et al., GCN 11160; Kuroda et al., GCN 11205) in g' and Rc bands. Photometric results and three sigma upper limit of the OT are listed below. We used SDSS catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic ---------------------------------------------------------------------- 3.15442 17:16:32 540.0 21.1 0.2 20.6 0.2 >20.1 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11280 SUBJECT: Swift-XRT refined analysis DATE: 10/09/15 11:37:28 GMT FROM: Owen Littlejohns at U of Leicester O. M. Littlejohns (U Leicester) reports on behalf of the Swift-XRT team: We have analysed 8.5 ks of XRT data for GRB 100915A (Littlejohns et al. GCN Circ. 11277), from 138 s to 18.8 ks after the BAT trigger. The data comprise 95 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 11279). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=0.9 (+0.6, -1.8). At T+320 s the decay steepens to an alpha of 2.4 (+0.6, -0.3). The light curve breaks again at T+1058 s to a decay with alpha=0.66 (+0.16, -5.16), before a final break at T+6126 s after which the decay index is 1.6 (+0.8, -0.3). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.37 (+0.21, -0.20). The best-fitting absorption column is 3.8 (+1.3, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 2.3 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.74 (+/-0.18) and a best-fitting absorption column of 4.6 (+1.0, -0.9) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 5.5 x 10^-11 (8.2 x 10^-11) erg cm^-2 count^-1. If the light curve continues to decay with a power-law decay index of 1.6, the count rate at T+24 hours will be 1.1 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.7 x 10^-14 (8.4 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00434178. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11401 SUBJECT: test og new gcncirc s/w grb DATE: 10/11/13 16:14:15 GMT FROM: Scott Barthelmy at NASA/GSFC test of new s/w //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11401 SUBJECT: GRB 10112A: MASTER optical observations DATE: 10/11/13 16:18:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres, S.Yazev, N.M.Budnev, Irkutsk State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located at Kislovodsk was pointed to the GRB101112A 21 sec s after notice time and 36 sec after GRB time at 2010-11-12 22:11:11.00 UT at very high zenit distance (~88 degrees). On our first (10s exposure) set we haven`t found optical transient within UNDEF error-box (ra=19 29 16 dec=+39 23 22 r=0.047500). The 5-sigma upper limit has been about 15.7 mag We have no found any OT at Liverpool OT position (Guidorzi et al., GCN Circ 11397). The message may be cited. mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11407 SUBJECT: Fermi GBM detection of a burst from a galactic source DATE: 10/11/15 16:45:48 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (USRA) and C. Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 311450068 at 17:54:26.74 UT on 14 November 2010, tentatively classified as Unreliable Location, is in fact a short, soft burst from a galactic source. The on-ground location, using the GBM trigger data, is RA = 264.3, Dec = -20.9 (J2000 degrees, equivalent 17h37m to -20d52m), with an uncertainty of 5.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to galactic coordinates: Long = 5.88, Lat = 5.85 (J2000 degrees). The angle from the LAT boresight is 55 degrees. The GBM light curve consists of one peak with an estimated duration of 32 ms (8-1000 keV). The time-averaged spectrum from T0-0.032 s to T0 is best fit by Optically Thin Thermal Bremsstrahlung with Epeak = 28.4 +/- 2.2 keV. The event fluence (10-1000 keV) in this time interval is (5.4 +/- 0.3)E-8 erg/cm^2. The 16-ms peak photon flux measured starting from T0-0.016 s in the 10-1000 keV band is 61.9 +/- 3.2 ph/s/cm^2. The location, duration and spectrum of the source indicate that this is a burst from a source in the galactic center region, typical of a magnetar burst. We suggest that this is a burst from SGR 1806-20, but the location uncertainty is too large to draw any firm conclusions on its nature. The temporal and spectral analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11428 SUBJECT: Swift detection of MAXIJ1409-619 DATE: 10/11/30 16:24:09 GMT FROM: Scott Barthelmy at NASA/GSFC V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), S. Campana (INAF-OAB), M. M. Chester (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/IASFPA), R. L. C. Starling (U Leicester) and G. Stratta (ASDC) report on behalf of the Swift Team: At 15:35:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located the previously-known source MAXI J1409-619 (trigger=439550). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 211.975, -61.988 which is RA(J2000) = 14h 07m 54s Dec(J2000) = -61d 59' 17" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows nothing obvious as is typical for a 10-min image trigger. No source was detected in the 2.5 sec promptly available XRT image. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 87 seconds with the White filter starting 1108 seconds after the BAT trigger. UVOT detected no new source within the BAT error circle. The GCN Notice sequence was complicated because of a 20-sec gap in TDRSS coverage (a hand-off from one TDRSS to the next satellite), so the initial BAT_Position message was lost, which was then immediately followed by a 14-min telemetry downlink pass for which the TDRSS messages are held on-board until the end of the pass. Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11574 SUBJECT: New feature in Fermi GBM GRB Ground Position Notices DATE: 11/01/17 04:19:13 GMT FROM: Valerie Connaughton at UAH/NSSTC Valerie Connaughton reports for the Fermi GBM Team: As of today, new information has been added to the GBM Ground Location GCN notices (GCN/FERMI_GBM_GND_POSITION) that will alert observers that a bright, hard burst has occurred in the LAT field-of-view. This additional information is derived from the limited real-time data extracted by the flight software, telemetered to the ground, and used to calculate the automated on-ground burst locations currently distributed in the notice within seconds - tens of seconds of the burst trigger. Background-subtracted count rates above 200 keV registered in the BGO detectors for events localized within 70 deg of the LAT boresight are used to flag the event. This is done for each of the localizations performed on the ground, so that it is possible that an event can be flagged as interesting in one notice and not in another, owing to brightness variations and spectral evolution in the burst. The background measure and integration time for the data provide less information than is available after the full data download hours later, so the method is not completely reliable, but it is fast and should permit observers to dedicate more effort to following up the sub-set of events that contains the LAT-detected burst population. The identification technique is susceptible to false positives in the case of short bursts, which can be mistakenly identified as bright owing to short integration times being more susceptible to statistical fluctuations above backgrounds measured in a fairly crude automated fashion. We have attempted to mitigate this by penalizing information obtained from integration times shorter than 64 ms, while still retaining the brighter short bursts. We have set a threshold which would have flagged 13 of the 18 high-confidence LAT detections between July 2008 and December 2010, with an additional 24 flagged events that are not high-confidence LAT detections (though some are low-confidence LAT detections). By lowering the threshold, we can identify all but two of the LAT high-confidence detections (GRB081215 was seen at 90 deg off-axis, and GRB100116 triggered on a precursor with the main, LAT-detected emission occurring 80 seconds later, beyond the time when the GBM FSW passes on the information for localization). Lowering the threshold this way comes at a cost of flagging 81 additional bursts (out of a total 575 GBM GRBs). Our thresholds can easily be altered upon feedback from the community. Statistical uncertainties on these types of localizations can be as low as 1 deg. An additional systematic error is associated with our localizations. Based on a study using 150 GRBs localized by other instruments (LAT, Swift BAT, SuperAGILE, INTEGRAL, MAXI, the InterPlanetary Network), this additional uncertainty is 3.2 deg for 70% of the automated ground locations distributed in these notices, and 9.5 deg for the remaining 30% (Briggs et al., in preparation). The GBM team is working to reduce these uncertainties. Please address feedback and questions tovalerie@nasa.gov //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11602 SUBJECT: IBAS Alerts n. 6130 and 6131 are not due to a GRB DATE: 11/01/26 16:23:55 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay) and E. Bozzo (ISDC Versoix) on behalf of the IBAS Localization Team report: IBAS Alerts n. 6130 and 6131 are not due to a GRB but to a known source (Sco X-1) not filtered correctly. This messages can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11673 SUBJECT: SGR-like outburst from the magnetar 1E 1841-04.5 DATE: 11/02/08 19:38:49 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), E. Sonbas (GSFC/USRA/Adiyaman Univ.) and G. Stratta (ASDC) report on behalf of the Swift Team: At 19:17:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from 1E 1841-04.5 (trigger=445033). Swift did not slew because of the Sun observing constraint. The BAT on-board calculated location is RA, Dec 280.306, -4.952 which is RA(J2000) = 18h 41m 13s Dec(J2000) = -04d 57' 06" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is 1.7 arcmin from the 1E 1841-04.5 location. The BAT light curve shows a single spike with a duration of about 0.15 sec. The peak count rate was ~24,000 counts/sec (15-350 keV), at 0 sec after the trigger. Due to the proximity to the Sun, this source will not be observable by XRT or UVOT until February 13th, 2011. BAT previously triggered on this source on May 6th, 2010 at 14:37:44 UT (GCN #10722). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11684 SUBJECT: Fermi GBM detection of a burst from 1E 1841-045 DATE: 11/02/09 23:31:51 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (USRA), S. Guiriec (UAH), C. Kouveliotou (NASA/MSFC) and D. Gruber (MPE) report on behalf of the Fermi/GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 318921267 at 05:14:25.93 UT on 9 February 2011, tentatively classified as a solar flare, may be a burst from a Galactic source, most likely the magnetar candidate 1E 1841-045. The on-ground location, using the GBM trigger data, is RA = 295.1, Dec = -1.7 (J2000 degrees, equivalent to 19h40m to -1d43m), with an uncertainty of 7.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to Galactic coordinates: Long =37.1, Lat = -11.7 (J2000 degrees). The angle from the LAT boresight is 50 degrees. The GBM light curve consists of one peak with a duration of ~32 ms (8-1000 keV). The time-averaged spectrum from T0-0.024 s to T0+0.016 s is best fit by Optically Thin Thermal Bremsstrahlung (OTTB) with Epeak = 51.7 +/- 7.7 keV, or a Black Body with kT = 11.7 +/- 0.7 keV. The event fluence (10-1000 keV) for the OTTB fit in this time interval is (5.8 +/- 0.6)E-8 erg/cm2. The 8-ms peak photon flux (measured starting at T0-0.016 s in the 10-1000 keV band) is 50.9 +/- 5.9 ph/s/cm2. The duration and spectrum of this trigger is typical of a magnetar burst. Given the location of the source and the report of the detection of a magnetar-like burst from 1E 1841-045 with Swift about 10 hours earlier (GCN 11673), we suggest that the GBM burst also originates from this source. We note that 1E 1841-045 was occulted by the Earth for GBM during the Swift trigger. The temporal and spectral analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11690 SUBJECT: Swift-BAT refined analysis of outburst from 1E 1841-04.5 DATE: 11/02/10 14:27:24 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC) (i.e. the Swift-BAT team): Using the data set from T-239 to T+221 sec from recent telemetry downlinks, we report further analysis of the outburst from 1E 1841-04.5 (trigger #445033) (Barthelmy, et al., GCN Circ. 11673). The BAT ground-calculated position is RA, Dec = 280.332, -4.939 deg, which is RA(J2000) = 18h 41m 19.7s Dec(J2000) = -04d 56' 19.9" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 97%. The mask-weighted light curve shows two pairs of overlapping peaks starting at ~T-0.02 and ending at ~T+0.15 sec. T90 (15-350 keV) is 0.1 +- 0.0 sec (estimated error including systematics). The time-averaged spectrum from T-0.008 to T+0.144 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.26 +- 0.66, and Epeak of 42.2 +- 3.2 keV (chi squared 54.4 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 7.5 +- 0.6 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.43 sec in the 15-150 keV band is 1.3 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/445033/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11747 SUBJECT: Fermi GBM detection of an SGR-like burst DATE: 11/02/17 23:58:29 GMT FROM: David Tierney at UCD D. Tierney (UCD), L. Lin (UAH), A.J. van der Horst (USRA) and C. Kouveliotou (NASA/MSFC) report on behalf of the Fermi/GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggered at 07:55:55.30 UT on 17 February 2011 (trigger 319622157 / 110217330). The event was tentatively classified as a solar flare, but it may be a burst from a Galactic source, most likely the magnetar candidate 1E 1841-045. The on-ground location, using the GBM trigger data, is RA = 279.4, Dec = -6.5 (J2000 degrees, equivalent to 18h38m to -6d27m), with an uncertainty of 2.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to Galactic coordinates: Long =25.6, Lat = 0.14 (J2000 degrees). The angle from the LAT boresight is 33 degrees. The GBM light curve consists of multiple peaks with duration of ~64 ms (8-1000 keV). The time-averaged spectrum from T0-0.048 s to T0+0.024 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is 0.13 ± 0.41 and the cutoff energy, parameterized as Epeak, is 44.52 ± 2.66 keV. The event fluence (10-1000 keV) in this time interval is (8.1 ± 0.5)E-8 erg/cm2. The 8-ms peak photon flux (measured starting at T0-0.016 s in the 10-1000 keV band) is 39.4 ± 5.5 ph/s/cm2. The duration and spectrum of this trigger is typical of a magnetar burst. Given the location of the source and the recent detections of magnetar-like bursts from 1E 1841-045 with GBM (GCN 11684) and Swift (GCN 11673), we suggest that this GBM burst also originates from this source. However, we cannot exclude the emergence of a new source or the activation of any of the other two magnetar candidates within the 3 sigma error box of GBM. The temporal and spectral analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11766 SUBJECT: IBAS distribution of coordinates for low significance INTEGRAL GRB triggers DATE: 11/02/24 16:18:42 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (INAF IASF-Milano), D.Gotz (CEA-Saclay), J. Borkowski (CAMK, Torun), M. Beck, C.Ferrigno (ISDC, Versoix), on behalf of the IBAS Localization Team announce: A new version of the IBAS Alert Distribution system is operational at the INTEGRAL Science Data Center. In addition to the already available functionalities, the new version distributes in real time also Alert Packets for low significance triggers discovered in the field of view of the IBIS imager. The new Alert Packets are called WEAK Alerts and are identified by the field PKT_TYPE=6 (see http://www.isdc.unige.ch/integral/science/grb#IBAS for details on the different Alert types). Users interested to receive the Alert Packets of the new type "WEAK" should contact the ISDC IBAS team (isdc-ibas@unige.ch). The threshold for the distribution of the usual high significance IBAS triggers remains unchanged at SIGMA= 8.0 (Alert Packets with PKT_TYPE= 3 (WAKEUP)) while the threshold for the distribution of low significance IBAS triggers is currently set at SIGMA= 6.5 (Alert Packets with PKT_TYPE= 6 (WEAK)) This threshold corresponds to a rate of a few WEAK Alert Packets per week, but it could be adjusted in the future. Many WEAK alerts will be produced by statistical fluctuations, but there is also a non negligible probability that some of them are due to real astrophysical events. In most cases it is not possible to recognize the GRBs based only on the INTEGRAL data, but the detection of afterglows could confirm some of these events as genuine GRBs. Several bursts that were confirmed by off-line interactive analysis of the INTEGRAL data produced triggers above the threshold currently adopted for the WEAK alerts. Recent examples include the two short bursts GRB 100703A (GCN Circ. n.10936) and GRB 110112B (GCN Circ. n.11562) and the long burst GRB 100909A (GCN Circ. n.11260). WEAK Alert Packets provide a single sky position, with error radius smaller than 4 arcmin. They are intended for robotic telescopes which can react without a negative impact on scheduled observing programmes. The value of SIGMA in the WEAK Alert Packet can be used as a figure of merit. WEAK Alert Packets may or may not be followed by the usual WAKEUP and/or REFINED Alert Packets, depending on the evolution of the detected signal. WEAK alerts for events belows WAKEUP threshold are neither confirmed nor cancelled with an OFFLINE packet. For further details see http://ibas.iasf-milano.inaf.it/IBAS_News.html It is recommended that current ibas clients upgrade their IBAS Client Software to the version 2.1.0 (available at http://www.isdc.unige.ch/integral/analysis#Software), although the previous versions should process WEAK alert without problems. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11775 SUBJECT: IBAS trigger n. 6138 is not a GRB DATE: 11/03/05 14:13:48 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay) on behalf of the IBAS localization Team reports: IBAS trigger n. 6138 is not due to a GRB but to 1A 0535+262, currently in outburst, that was not corretcly localized due to incorrect attitude information at satellite level. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11884 SUBJECT: ICSP VLF observation of multiple SGR-like bursts from 1E 1841-045 on Feb. 9, 2011 DATE: 11/04/05 12:30:16 GMT FROM: Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci. ICSP VLF observation of multiple SGR-like bursts from 1E 1841-045 on Feb. 9, 2011 Sushanta K. Mondal (ICSP), Sandip K. Chakrabarti (S. N. Bose Centre and ICSP), Debashis Bhowmick (ICSP) We observed several sudden ionospheric disturbances on Feb. 9th, 2011 in signals transmitted from several stations. One of them (occurring at 05:14:26 UT) coincided exactly with the observed time of Fermi (GCN #11684) but there were many both before and after within a few hundred seconds. All these events were observed in both phase and amplitude, indicating that the disturbances were real. One image of the amplitude/phase from various transmitting stations as obtained by our receiver at Sitapur station is in http://www.bose.res.in/~chakraba/gbm090211.html. The entire set of events were riding on a 'B' type flare, but we suspect our events are not parts of any solar flare, as the time durations of the signals involved appear to be too short (similar to our GRB090424 for our VLF signal; see GCN No.11883) Since GCN #11684 observes only one signal (corresponding to spikes at 18866s in our Figure), we request others to check if there were any observations at the times when other VLF signals were seen. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11987 SUBJECT: Fermi-GBM data processing and delivery DATE: 11/05/01 19:20:40 GMT FROM: Julie McEnery at NASA/GSFC Valerie Connaughton (UAH) reports for the GBM team in Huntsville: The tornadoes on April 27 knocked out much of the power and communications infrastructure in Huntsville and the surrounding region. There is no link between Mission Operations and the GBM Instrument center in Huntsville and thus no transfer to or processing of data for analysis or delivery to the FSSC. Communication of real time burst locations via GCN notices continues unhindered because the required processing occurs at GSFC. Estimates for the restoration of power to the region range from mid next week to 15-30 days hence. Data processing and delivery of new and backlogged files will be announced on the Fermi mission webpage (http://fermi.gsfc.nasa.gov) when power is restored in Huntsville. Limited transfer to and processing of burst data is occurring at MPE in Munich. Refined ground analysis of GBM triggers will be announced via GCN circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12042 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 328195911 is not a GRB DATE: 11/05/27 14:46:16 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 328195911 (110527.564) at 13:31:49.73 UT on 27 May 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12076 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 110621949 is not a GRB DATE: 11/06/22 15:01:17 GMT FROM: Adam Goldstein at Fermi-GBM/UAH A. Goldstein (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 110621949 at 22:46:42 UT on 21 June 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a local particle event." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12079 SUBJECT: SGR 1E 1841-045: Swift detection of a soft gamma repeater burst DATE: 11/06/23 15:06:07 GMT FROM: Scott Barthelmy at NASA/GSFC A. Rowlinson (U Leicester), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), C. A. Swenson (PSU) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift Team: At 14:41:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1E 1841-045 / Kes 73 (trigger=455904). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 280.317, -4.937, which is RA(J2000) = 18h 41m 16s Dec(J2000) = -04d 56' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 0.06 sec. The peak count rate was ~8000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 14:43:09 UT, 86 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec = 280.33047, -4.93562 which is equivalent to: RA(J2000) = 18h 41m 19.3s Dec(J2000) = -04d 56m 08.2s with an uncertainty of 4.6 arcseconds (radius, 90% containment), which is 2.9 arcseconds from the location of 1E 1841-04.5 (AKA PSR J1841-0456). This position may be improved as more data are received. UVOT took a finding chart exposure of 150 seconds with the white filter starting 89 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the large, but uncertain extinction expected. Swift has previously triggered on bursts from this source (most recently on February 8, 2011, GCN 11673, Barthelmy et al.). Burst Advocate for this burst is A. Rowlinson (bar7 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12082 SUBJECT: SGR 1E 1841-045: Swift-BAT refined analysis DATE: 11/06/23 18:12:20 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), A. Rowlinson (U Leicester), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+302 sec from the recent telemetry downlink, we report further analysis of event from SGR 1E 1841-045 (trigger #455904) (Rowlinson, et al., GCN Circ. 12079). The BAT ground-calculated position is RA, Dec = 280.329, -4.934 deg, which is RA(J2000) = 18h 41m 19.0s Dec(J2000) = -04d 56' 00.9" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 18%. The mask-weighted light curve shows a single spike that starts at ~T_zero and ends at ~T+0.04 sec. T90 (15-350 keV) is 0.020 +- 0.009 sec (estimated error including systematics). The time-averaged spectrum from T-0.0 to T+0.1 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.04 +- 0.91, and Epeak of 32.8 +- 4.7 keV (chi squared 43.0 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T-0.43 sec in the 15-150 keV band is 3.6 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.68 +- 0.15 (chi squared 85.2 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/455904/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12083 SUBJECT: Swift J185003.2-005627: Swift detection of a burst from a new Galactic transient DATE: 11/06/25 00:32:47 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), W. H. Baumgartner (GSFC/UMBC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. Pagani (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), C. J. Saxton (UCL-MSSL), M. H. Siegel (PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 00:06:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located an unknown source (trigger=456014). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 282.551, -0.968 which is RA(J2000) = 18h 50m 12s Dec(J2000) = -00d 58' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 2 sec. The peak count rate was ~400 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 00:07:42.4 UT, 94.8 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 282.5134, -0.9410 which is equivalent to: RA(J2000) = 18h 50m 03.21s Dec(J2000) = -00d 56' 27.5" with an uncertainty of 5.4 arcseconds (radius, 90% containment). This location is 166 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 250 seconds with the U filter starting 263 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. Data from the list of sources generated on-board are not available at this time. Given the soft nature of the initial BAT detection and the proximity to the Galactic plane (7 arcmin) we believe that this is probably a previously-unknown Galactic transient, rather than a cosmological GRB, which we name 'Swift J185003.2-005627'. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12084 SUBJECT: Swift J185003.2-005627: TAROT Calern observatory optical observations DATE: 11/06/25 00:52:03 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of Swift J185003.2-005627 detected by SWIFT (trigger 456014, Beardmore et al. 2011 GCNC 12083) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 133.0s after the GRB trigger. The elevation of the field increased from 45 degrees above horizon and weather conditions were very good. Galactic coordinates are lon= 31.9297 lat= -0.1669 that leads to a very high galactic extinction in R band. The date of trigger : t0 = 2011-06-25T00:06:07 The first image is 30.0s exposure in tracking mode. No new source is detected in the XRT error box: t0+133.0s to t0+163.0s : R > 16.8 Until 1200 seconds after the trigger, no new source is detected in subsequent images. The field of view was also observed from TAROT La Silla (Chile) but the elevation is low (11 deg) and limiting magnitudes are not better. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12085 SUBJECT: Swift J185003.2-005627: TAROT La Silla observatory optical observations DATE: 11/06/25 01:21:30 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of Swift J185003.2-005627 detected by SWIFT (trigger 456014, Beardmore et al. 2011 GCNC 12083) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 53.6s after the GRB trigger (10.2s after the notice), i.e 80s before the first optical observation reported from TAROT Calern (see Klotz et al. 2011 GCNC 12084). The elevation of the field increased from 10 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT with a limiting magnitude of: t0+53.6s to t0+113.6s : R > 15.4 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12086 SUBJECT: Swift J185003.2-005627: Swift-BAT refined analysis DATE: 11/06/25 12:34:42 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+302 sec from recent telemetry downlinks, we report further analysis of Swift J185003.2-005627 (trigger #456014) (Beardmore, et al., GCN Circ. 12083). The BAT ground-calculated position is RA, Dec = 282.509, -0.946 deg which is RA(J2000) = 18h 50m 02.2s Dec(J2000) = -00d 56' 47.3" with an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a single pulse starting at ~T-2 sec, peaking at ~T+4 sec, and ending at ~T+14 sec, entirely in the lowest energy band (15-25 keV). T90 (15-350 keV) is 12.0 +- 4.5 sec (estimated error including systematics). The time-averaged spectrum from T-1.7 to T+13.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 5.11 +- 0.98. The fluence in the 15-150 keV band is 1.6 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.28 sec in the 15-150 keV band is 0.6 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/456014/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12087 SUBJECT: Swift J185003.2-005627: Swift-XRT/UVOT refined analysis DATE: 11/06/25 16:51:02 GMT FROM: Andy Beardmore at U Leicester A. P. Beardmore (U. Leicester), S. Campana (INAF-OAB), J. A. Kennea (PSU) and C. A. Swenson (PSU) report on behalf of the Swift/XRT and UVOT teams: We have analysed 2.8 ks of Swift/XRT data from the transient Swift J185003.2-005627 (Beardmore, et al., GCN Circ. 12083), from 88 s to 17.5 ks after the BAT trigger. The data comprise 421 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The astrometrically corrected X-ray position for this source (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue), derived from 1660 s of XRT Photon Counting mode data and 2 UVOT images, is RA, Dec = 282.51390, -0.93980 which is equivalent to: RA (J2000): 18 50 3.33 Dec (J2000): -00 56 23.3 with an uncertainty of 1.7 arcsec (radius, 90% confidence). This position may be improved as more data are received. The position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). The X-ray light curve initially decays like a powerlaw, with an index of 1.158 (+0.102, -0.125), before flattening to a slope of 0.161 (+0.035, -0.072) at T +365 (+109, -40) s after the trigger. A spectrum formed from the WT mode data from T+101 to T+429 s after the trigger is best fit by an absorbed blackbody, with a temperature of 0.83 +/- 0.03 keV and column density of 1.71 +/- 0.19 x 10^22 cm^-2, consistent with the Galactic column in the direction of the source (Kalberla et al. 2005). The observed (unabsorbed) 0.3-10 keV flux for this spectrum is 4.85e-10 (6.76e-10) ergs cm^-2 s^-1. The XRT spectrum, together with the soft BAT spectrum reported by Markwardt et al. (GCN Circ. 12086) and the location of the source in the Galactic plane, is suggestive of emission from a type I burst. Swift/UVOT observations of the field were also performed but no optical counterpart is detected at the XRT position. Preliminary 3-sigma upper limits, using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627), are: Filter T_start(s) T_stop(s) Exp(s) Mag --------------------------------------------------------------------------- white 104 5305 628 >18.9 v 593 1763 136 >17.2 b 519 1863 136 >18.9 u 263 1837 382 >19.9 w1 642 1813 130 >19.7 w2 742 5340 125 >20.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 16.09 in the direction of the transient (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12090 SUBJECT: Swift J185003.2-005627: NIR Observation DATE: 11/06/26 01:09:55 GMT FROM: Myungshin Im at Seoul Nat U Myungshin Im, Ji Hoon Kim, and Changsu Choi (CEOU/Seoul National University) on behalf of a larger collaboration We observed Swift J185003.2-005627 (Beardmore et al. GCN 12083) in K-band with UKIRT starting at 2011 June 25, 08:50:09 UT. Within the enhanced XRT/UVOT error circle (Beardmore et al. GCN 12087), we identify a NIR source with K ~ 14.8 mag, at the position of RA=18:50:03.27 and Dec=-00:56:23.2. However, no strong variability is detected over the time span of 3 hours. The source density is very high in this field too. Judging from these facts, it is very unclear if this source is associated with the transient. Further observation is planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12101 SUBJECT: Swift J185003.2-005627: 1.23m CAHA and BOOTES-3 observations DATE: 11/06/29 23:48:36 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC), V. Terron (IAA-CSIC), P. Ferrero (IAC & U. La Laguna, Tenerife), J.C. Tello(IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), W. Allen (Vintage Lane Obs, New Zealand), M. Jelinek (IAA-CSIC), P. Kubanek (IAA-CSIC & U. Valencia), M. Fernandez (IAA-CSIC), report on behalf of a larger collaboration: "We imaged the field of Swift J185003.2-005627 (Beardmore et al., GCN 12083) with the 1.23m telescope of Calar Alto observatory (Almeria, Spain) and the 0.6m Yock-Allen BOOTES-3 telescope (Vintage Lane Observatory, New Zealand). The 1.23m observations are composed of 90x90s I-band images taken on June 25.03138 -- 25.15559 UT (i.e, starting 39.1 min after the trigger). The BOOTES-3 observations were carried out in the Y and Z-bands on June 25.33336-25.76840 UT. In the 1.23m co-added image, we detect a I ~21 source at RA(J2000)=18:50:03.29, DEC(J2000)=-00:56:23.0 (+/-0.7") which is consistent with the object reported by Im et al. (GCN 12090). A preliminary analysis of the individual 1.23m images shows no obvious flaring activity at the position of the object above the limiting magnitude of each single exposure (I ~19, 3 sigma). A preliminary search for YZ-band flares in the BOOTES-3 images provided also negative results, however we note that the YZ-band analysis was heavily limited by the presence of the nearby R = 16.1 star located at RA(J2000)=18:50:04.015, DEC(J2000)=-00:56.23.44." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12103 SUBJECT: SGR 1E 1841-045: Swift detection of a soft gamma repeater burst DATE: 11/07/02 09:01:09 GMT FROM: Scott Barthelmy at NASA/GSFC A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC), M. M. Chester (PSU), N. P. M. Kuin (UCL-MSSL), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC) and B. Sbarufatti (INAF-OAB/IASFPA) report on behalf of the Swift Team: At 08:38:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1E 1841-045 / Kes 73 (trigger=456505). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 280.314, -4.948, which is RA(J2000) = 18h 41m 15s Dec(J2000) = -04d 56' 53" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of less than 0.064 sec. The peak count rate was ~10,300 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 08:39:49.8 UT, 71.1 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 280.33084, -4.93597 which is equivalent to: RA(J2000) = 18h 41m 19.40s Dec(J2000) = -04d 56' 09.5" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.8 arcseconds from that of a known X-ray source: 2XMM J184119.2-045611 in the XMM-NEWTON XMMSSC catalogue. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.57 x 10^22 cm^-2, Kalberla et al. 2005), with an excess column of 1 (+1.17/-0.92) x 10^22 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 74 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. No correction has been made for the large, but uncertain extinction expected. Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12104 SUBJECT: SGR 1E 1841-045: Swift-BAT refined analysis DATE: 11/07/02 14:22:58 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-120 to T+182 sec from the recent telemetry downlink, we report further analysis of SGRB 1E 1841-045 (trigger #456505) (Melandri, et al., GCN Circ. 12103). The BAT ground-calculated position is RA, Dec = 280.349, -4.953 deg, which is RA(J2000) = 18h 41m 23.8s Dec(J2000) = -04d 57' 09.6" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single spike starting at ~T-0.01 sec and ending at ~T+0.04 sec. T90 (15-350 keV) is 0.036 +- 0.012 sec (estimated error including systematics). The time-averaged spectrum from T-0.004 to T+0.032 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.89 +- 0.4. The 1-sec peak photon flux measured from T-0.48 sec in the 15-150 keV band is 1.1 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/456505/BA/ We note the recent activity of this source: Swift BAT trigger 445776 on 11 Feb 2011, and trigger 455904 on 23 Jun 2011 (GCN 12079 & 12082). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12105 SUBJECT: SGR 1E 1841-045: early optical limit by "Pi of the Sky" DATE: 11/07/02 14:34:17 GMT FROM: Marcin Sokolowski at Soltan Inst. Nuc Studies,Warsaw M.Sokolowski,T.Batsch,A.Majcher,A.Majczyna,K.Nawrocki,J.Uzycki,G.Wrochna (IPJ, Swierk), M.Cwiok,W.Dominik,L.W.Piotrowski,A.F.Zarnecki (University of Warsaw), K.Malek,L.Mankiewicz,R.Opiela,M.Siudek,V.Repei (CFT PAN), G.Kasprowicz,M.Zaremba (Warsaw University of Technology), from the "Pi of the Sky" collaboration ( http://grb.fuw.edu.pl ). A. Maury ( San Pedro de Atacama Celestial Explorations ) The wide field "Pi of the Sky South" apparatus, installed in the private observatory of Alain Maury in San Pedro de Atacama ( http://grb.fuw.edu.pl/pi/index.html#spda_site.htm ), collected images of field of SGR 1E 1841-045, just before and 68 seconds after the Swift-BAT trigger ( 456505 ). No new source brighter than 11.5 mag has been identified on 10s exposures: t_start - t0 start (UT) end (UT) 3-sigma limit -10 08:38:28 08:38:38 11.5 +68 08:39:46 08:39:56 11.5 where limit is based on nearby reference stars magnitudo in V filter. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12106 SUBJECT: Swift-BAT trigger 456532 is not astrophysical DATE: 11/07/03 00:07:53 GMT FROM: Scott Barthelmy at NASA/GSFC B. Sbarufatti (INAF-OAB/IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. J. Saxton (UCL-MSSL), M. H. Siegel (PSU) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team: At 23:47:50 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=456532). Swift slewed immediately to the calculated location: RA, Dec 318.634, -46.745, which is RA(J2000) = 21h 14m 32s Dec(J2000) = -46d 44' 42" The lightcurve does not show anything significant and the peak in the image plane is of marginal significance (less than 7 sigma). The XRT began observing the field at 23:49:22.2 UT, 92.0 seconds after the BAT trigger. No source was detected in 230 s of promptly downlinked data. UVOT took a finding chart exposure of 124 seconds with the U filter starting 254 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.2 mag. Data from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. Given the above low significances and non-detections, we conclude that this trigger is not due to anything astrophysical, and is just a chance coincidence of noise in the rate and image domains. Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12107 SUBJECT: Swift Trigger 456659 is probably not astrophysical DATE: 11/07/05 10:05:01 GMT FROM: David Palmer at LANL V. Mangano (INAF-IASFPA), W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB), M. M. Chester (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), O. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 09:21:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 456659. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 45.476, +2.977 which is RA(J2000) = 03h 01m 54s Dec(J2000) = +02d 58' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). At present we do not have data to characterize this trigger. We believe that the trigger occurred on the rising edge of the South Atlantic Anomaly. Also, the trigger significance is 6.7 which is less than 7 sigma. Thus, the trigger is likely to be non-astrophysical. The XRT began observing the field at 09:22:32.2 UT, 84.5 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. Due to a telemetry outage, further information will require the Malindi downlinked data in a couple of hours. At that time it will be possible to determine the reality of this event. Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12109 SUBJECT: Swift trigger 456780 is not a burst DATE: 11/07/07 08:08:14 GMT FROM: Wayne Baumgartner at GSFC W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), V. D'Elia (ASDC), P. A. Evans (U Leicester), C. Gronwall (PSU), C. Guidorzi (U Ferrara), E. A. Hoversten (PSU), O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA), K. L. Page (U Leicester), J. L. Racusin (NASA/GSFC), P. Romano (INAF-IASFPA) and B. Sbarufatti (INAF-OAB/IASFPA) report on behalf of the Swift Team: At 07:48:43 UT, the Swift Burst Alert Telescope (BAT) triggered on trigger=456780. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 22.861, +16.758 which is RA(J2000) = 01h 31m 27s Dec(J2000) = +16d 45' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a rapidly rising background as the spacecraft entered the SAA. In addition to the fact that the image significance was less than the 7 sigma canonical threshold, this trigger is not a burst. The XRT began observing the field at 07:49:44.2 UT, 60.9 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. No prompt UVOT data products were received. We are waiting for the full dataset to search for a UVOT counterpart. Burst Advocate for this burst is W. H. Baumgartner (wayne AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12147 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 332078586 is not a GRB DATE: 11/07/11 15:04:29 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 332078586 (110711502) at 12:03:04.37 UT on 11 July 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12149 SUBJECT: Swift Trigger 457076: a possible GRB DATE: 11/07/11 20:16:56 GMT FROM: David Burrows at PSU/Swift H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), S. Campana (INAF-OAB), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), C. J. Saxton (UCL-MSSL), G. Stratta (ASDC), C. A. Swenson (PSU), G. Tagliaferri (INAF-OAB) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 19:44:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB (trigger=457076). Swift slewed immediately to the on-board location. The BAT on-board calculated location is RA, Dec 344.491, -65.600, which is RA(J2000) = 22h 57m 58s Dec(J2000) = -65d 36' 00" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows nothing significant, which is typical for an image trigger. We note that because of an observing constraint, Swift slewed 2.9 minutes after the trigger, so there will be little real-time XRT and UVOT data on this target. The XRT began observing the field at 19:47:29.9 UT, 153.1 seconds after the BAT trigger. No source was detected in 135 s of promptly downlinked data. We are waiting for the full dataset to search for an XRT counterpart. UVOT took a finding chart exposure of 144 seconds with the White filter starting 157 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Due to the marginal significance of the trigger (7.04 sigma), the loss of some TDRSS data due to a telemetry dump, and the delayed and short observation of the source with the narrow field instruments, we will not be able to confirm or refute this event as a GRB until we have analyzed the full downlinked data. Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12154 SUBJECT: Swift trigger 457076 is not a GRB DATE: 11/07/12 12:26:04 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),V. D'Elia (ASDC), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL), G. Stratta (ASDC) Based on a non-detection in the XRT and a low significance in the BAT, we conclude thatSwift/BAT trigger 457076 (Krimm et al, GCN 12149) was most likely caused by a chance fluctuation in the BAT image domain and is not due to a burst or other astrophysical phenomenon. XRT began observing the field of the Swift trigger 457076 (Krimm et al., GCN circ 12149) 167 s after the burst trigger. We analyzed the first 2.6 ks of XRT data, from 167 s until 10 ks after the trigger. No candidate afterglow is detected in the BAT error circle, and the three sigma upper limit for any new source in the field of view is 4.3e-3 counts/second. We examined the BAT event data from T-60 to T+243, when a slew took the trigger position out of the field of view. The significance of the event is reduced in ground processing to 5.5 sigma. The light curve shows a positive excess in the two lowest energy bands as would be expected from an image trigger, but the increase is only during the trigger interval, and the two bands are only weakly correlated with each other. There is no indication of earlier or later emission. This result, combined with the null result from the XRT, leads us to our conclusion. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12159 SUBJECT: Swift J1822.3-1606: A Probable New SGR in Ground Analysis of BAT Data DATE: 11/07/15 17:35:23 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift Swift J1822.3-1606: A Probable New SGR in Ground Analysis of BAT Data J. R. Cummings (GSFC/UMBC), D. Burrows (PSU), S. Campana (INAF-OAB), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), S. Zane (MSSL-UCL) on behalf of the Swift Team At 2011-07-14 at 12:47:47.1 UTC, Swift-BAT triggered (#457261) on a previously unknown source, Swift J1822.3-1606. This was at the same time as Fermi-GBM trigger #332340476. Only a subthreshold source was detected onboard. There were two subsequent rate increases of similar size, probably from the same source at about T+26 sec and T+308 sec, the latter also causing a rate trigger with no significant source found onboard (#457263). There were also 2 other rate triggers within the same pointing period (about 1650 seconds long), but no significant flux was observed from the source at these times. Each pulse was about 0.005 +- 0.001 sec long. All the emission was < 100 keV. Because of the repeated soft and short rate increases, and the location of the source near the Galactic plane, we tentatively classify this object as a new Soft Gamma-ray Repeater. Combining BAT pulse-height events from the two rate triggers yields a highly significant source detection at RA, Dec 275.595, -16.100, which is: RA (J2000) 18h 22m 22.8s Dec (J2000) -16d 05' 59" with an estimated error of 2.3 arcmin (estimated radius, 90% containment). There was also a rate trigger (#457253) on a longer (~0.1 sec), larger, and harder event that was out of the BAT field of view at T-10754 sec. SWIFT J1822.3-1606 was above the horizon and out of the BAT FOV, and we cannot determine if the event was associated with the source or not. The Swift/BAT hard X-ray transient archive was examined to search for previous emission from SWIFT J1822.3-1606 in daily averages. No significant excess was found back to 2011 June 15 with an average 1-sigma error in the 15-50 keV band of 0.0016 ct/s/cm2 (~7 mCrab). The history of Swift/BAT on-board source detections was examined and we found no previous rate-triggered or image- triggered detections of the source. We have detailed data for two rate increases. A powerlaw fit to the combined spectrum has a photon index of 3.7 +- 0.5. A blackbody fit to the combined spectrum has a marginally better chisquared with a temperature of 4.9 +- 0.5 keV. The combined fluence of the two rate increases for which we have data, using the blackbody model, was (2.0 +- 0.4) x 10^-7 ergs/cm^2 A Swift TOO has been approved, but the source is Moon constrained until at least 17:34 UT on July 15. An observation is planned soon after the source comes out of constraint. This circular has also been posted as ATel #3488: http://www.astronomerstelegram.org/?read=3488 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12163 SUBJECT: Swift J1822.3-1606: Swift-XRT detection of the X-ray counterpart DATE: 11/07/16 00:33:30 GMT FROM: Claudio Pagani at U of Leicester C. Pagani, A. P. Beardmore (U. Leicester), J. A. Kennea (PSU) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift-XRT team. We have analysed 584 s of Photon Counting (PC) XRT data for Swift J1822.3-1606 (Cummings et al. GCN Circ. 12159),  a probable SGR.  The XRT observations started 1.2 days after the  BAT trigger. A bright, uncatalogued X-ray source is detected inside the BAT error circle at RA, Dec 275.5763, -16.0742 which is equivalent to:   RA(J2000)  = 18h 22m 18.32s   Dec(J2000) = -16d 04' 27.2" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 113 arcseconds from the BAT position. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12167 SUBJECT: Swift J1822.3-1606 DATE: 11/07/16 16:23:27 GMT FROM: Ersin Gogus at Sabanci U/Turkey Ersin Gogus (Sabanci Univ. Istanbul), Chryssa Kouveliotou (NASA/MSFC), Tod Strohmayer (NASA/GSFC) report on behalf of a larger team: RXTE/PCA observed the new source, Swift J1822.3-1606 (Cummings et al. GCN Circ. 12159) on 2011 July 16, for 6.7 ks. We performed a timing analysis on the barycentered data and detected a coherent pulsation at 0.1185149(2) Hz corresponding to 8.4377585 s. Pulsations are clearly visible in the PCA light curve. The peak-to-peak pulsed amplitude in the 2-10 keV band is 0.41. This pulsed fraction is highly unlikely from an SGR source, and very reminiscent of the outburst onset of Swift J1626.6-5156 (Palmer et al. 2005), that is likely a Be-X-ray binary system. Alternatively, the source could be similar to the rotation powered PSR J1846-0258 (Gavriil et al. 2008), which was observed to emit SGR-like outbursts. Further multi-wavelength observations of the source are strongly encouraged to determine its nature. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12170 SUBJECT: Swift J1822.3-1606: Transient Magnetar or Be X-ray Binary? DATE: 11/07/18 23:39:04 GMT FROM: Jules Halpern at Columbia U. Gogus et al. (GCN 12167) and Gorosabel et al. (ATel #3496) have proposed that the recently detected 8.43 s pulsar Swift J1822.3-1606 (Cummings et al., GCN 12159) may be a transient Be/X-ray binary like the 15.3 s pulsar Swift J1626.6-5156, rather than a magnetar. These suggestions were motivated by the large pulsed fraction of 41%, and a candidate 2MASS IR counterpart in the 1.8" radius X-ray error circle (as refined by Pagani et al., ATel #3493). However, the relatively small X-ray column of 3e21 cm^-2 for a power-law plus blackbody fit (Esposito et al., ATel #3490), together with the colors of the 2MASS star and lack of a bright optical detection, are incompatible with a B star companion. The intrinsic colors of an early B star, for example, type B1V, are J-K = -0.14, V-K = -0.76. In contrast, the 2MASS candidate has K = 11.63, J-K = 2.43, and V-K > 9 (from its absence on red and blue Sky Survey plates). The implied color excess E(V-K) > 10 for a B star is inconsistent with the X-ray column density 3e21 cm^-2, the latter corresponding to only ~1.7 magnitudes of extinction in V. A B1V star of absolute magnitude M_V = -3.14 at an assumed distance of 3 kpc should then have apparent V ~ 10.9, which is strongly contradicted by the non-detection. (See Reig et al., arXiv:1106.4671, for analogous discussion of the actual V = 15.5 optical counterpart of Swift J1626.6-5156, which has 3 times larger X-ray column than Swift J1822.3-1606.) Instead, the X-ray properties of Swift J1822.3-1606 may be similar to those of the 2003 outburst of the transient AXP XTE J1810-197 (Gotthelf & Halpern 2007, Ap&SS, 308, 79), including the latter's initial 2-10 keV flux of ~1e-10 erg cm^-2 s^-1, initial pulsed fraction of ~50%, X-ray column density of 6e21 cm^-2, distance of 3-4 kpc (Minter et al. 2008, ApJ, 676, 1189), and short (~1 s) bursts (Woods et al. 2005, ApJ, 629, 985). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12179 SUBJECT: Swift J1822.3-1606 : Fermi GBM observation DATE: 11/07/19 15:58:48 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) and Chryssa Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "At 12:47:54.38 UT on 14 July 2001, the Fermi Gamma-Ray Burst Monitor triggered (trigger 332340476 / 110714533) on a very short event with a soft spectrum. The source of the emission was later identified as a new source, Swift J1822.3-1606 (Cummings et al. GCN Circ. 12159). The GBM on-ground location is consistent with the Swift position. The event duration is approximately 8 ms. Its spectrum is adequately fit with either an optically thin thermal bremsstrahlung (OTTB) model of kT = 37 +/- 5 keV or a power law with an exponential cutoff (COMPT) with index = 0.2 +/- 0.6 and Epeak = 40 +/-3 keV. The event fluence (10-1000 keV) is ~4 x E-08 erg/cm2. Visual observation of the GBM data revealed at least three and possibly four additional events near the trigger time ranging in duration between 10 - 30 ms. Preliminary analysis indicates a harder spectrum for these non-triggered events. " //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12186 SUBJECT: Recent GCN/Swift-BAT Slew Burst Position notices are due to playback debugging DATE: 11/07/20 22:21:45 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC) writes: To GCN Notice Recipients (socket-based & email-based): The recent series of four copies of the BAT Slew Burst position Notice (ID_NUM 575 and RA,Dec=222.720,+41.310) are all due to my debuging a problem in a related part of GCN. They are all playback copies of a previously real notice. I forgot to turn on the block2world filter for this notice type while doing the playback debugging. Please totally disregard the 4 notices in the last hour. My sincere apologies for the confusion and lost effort in chasing these repeated notices. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12208 SUBJECT: Swift triggers 458268 and 458269 are not astrophysical DATE: 11/07/28 03:38:40 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy (GSFC) on behalf of the Swift Team reports: The startracker on Swift has lost lock, so erroneous ACS information has caused the two recent BAT triggers (458268 and 458269) to misidentify two known sources as unknown sources. Please disregard these two sets of GCN/Swift Notices. Further GCN/Swift trigger notices are being blocked to world distribution. The Flight Operations Team is currently recovering the Startracker to normal operations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12209 SUBJECT: Swift detection of a SGR-like burst from the AXP 4U 0142+61 DATE: 11/07/29 11:52:33 GMT FROM: David Palmer at LANL S. R. Oates (UCL-MSSL), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), N. Gehrels (NASA/GSFC), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/IASFPA) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift Team: At 11:19:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located on a short burst from the AXP 4U 0142+61 (trigger=458345). Swift slewed immediately to the source location. The BAT on-board calculated location is RA, Dec 26.598, +61.729 which is RA(J2000) = 01h 46m 24s Dec(J2000) = +61d 43' 43" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 0.1 sec. The peak count rate was ~3500 counts/sec (15-350 keV), at ~0.1 sec after the trigger. The XRT began observing the field at 11:20:38.1 UT, 82.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright source with an enhanced position: RA,Dec = 26.5937, 61.7510 (degrees) which is equivalent to: RA (J2000.0) = 01 46 22.48 DEC (J2000.0) = +61 45 03.6 with an uncertainty of 2.2 arcsec (radius, 90% containment). This is consistent with the position of 4U 0142+61. UVOT took a finding chart exposure of 150 seconds with the White filter starting 93 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. Swift has been regularly monitoring this source 4U 0142+61 as part of program of regular monitoring of AXPs (PI: V. Kaspi). This AXP has previously been seen to emit SGR-like bursts (e.g. ATEL #794, Kaspi et al., 2006) Burst Advocate for this burst is S. R. Oates (sro AT mssl.ucl.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12211 SUBJECT: AXP 4U 0142+61: Swift-BAT refined analysis DATE: 11/07/29 20:46:05 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-120 to T+180 sec, we report further analysis of AXP 4U 0142+61 (trigger #458345) (Oates, et al., GCN Circ. 12209). The mask-weighted light curve in 8 msec binning shows at least 10 short bursts in the available data. The burst times are, T-12.368 sec, T+0 sec (triggered burst), T+1.336 sec, T+23.528 sec, T+61.632 sec, T+84.784 sec, T+137.688 sec, T+157.224 sec, T+162.432 sec and T+162.856 sec where T = 11:19:15.398 UT. The triggered burst at T+0 sec has the brightest pulse. T90 (15-350 keV) of this brightest burst is 5 +- 1 msec (estimated error including systematics). The time-averaged spectrum of this brightest burst from T+0.001 sec to T+0.006 sec is best fit by a blackbody model. The blackbody temperature is 6.7 +- 1.0 keV (chi square 55.9 for 57 d.o.f.). The fluence in the 15-150 keV band is 1.2 +- 0.4 x 10^-7 erg/cm2. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/458345/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12213 SUBJECT: INTEGRAL Weak trigger #6331: GRT Optical Observation DATE: 11/07/30 05:05:52 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (UMD/GSFC), N. Gehrels (GSFC), T. Okajima (GSFC), Y. Urata (NCU) We observed the field of INTEGRAL Weak trigger #6331 with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). A total 204 good quality images of 5 sec (146 images), 30 sec (31 images) and 60 sec (27 images) exposures were taken in the R filter starting from July 27 04:05:04 (UT), about 102 seconds after the trigger (92 seconds after the notice), and stopped on July 27 06:57:47 (UT). We do not detect the optical afterglow both in the individual images and the stacked image inside the 3.63 arcmin error circle. The estimated five sigma upper limit of the combined image (total exposure of 3280 sec) is ~19.8 mag using the USNO-B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12231 SUBJECT: AXP 4U 0142+61: Fermi GBM detection DATE: 11/08/01 21:47:33 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 333654039 at 17:40:37.14 UT on 29 July 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a short burst from AXP 4U 0142+61 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12248 SUBJECT: Fermi GBM trigger 334123030 (110804165) is not a GRB DATE: 11/08/04 16:57:51 GMT FROM: David Tierney at UCD D. Tierney (UCD), reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 334123030 (110804165) at 03:57:08.01 UT on 04 August 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12250 SUBJECT: Reprocessed enhanced Swift-XRT positions and GRB products DATE: 11/08/05 15:00:15 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports, The UK Swift Science Data Centre (http://www.swift.ac.uk) has reprocessed all the on-line GRB data products (XRT light curves, spectra, enhanced positions and the Burst Analyser) using the latest software and calibration. For light curves and spectra the differences between the new and previous results are small or negligible. By August 2011 our 90% confidence GRB enhanced positions were in agreement with UVOT OT positions in 80% of the cases. We have re-calibrated the UVOT-XRT mapping, updated our software to use a time-dependent mapping, and rebuilt the enhanced GRB positions; a new table is online at http://www.swift.ac.uk/xrt_positions. These new positions agree with those from the UVOT at the 90% level, thus verifying the enhanced position errors quoted. Note that the position changes are small, the median shift being 0.8 arcsec. For details of this reprocessing effort, see: http://www.swift.ac.uk/reprocessed.php //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12252 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 110806.263 is not a GRB DATE: 11/08/06 18:20:19 GMT FROM: Sinead McGlynn at Excellence Cluster/TUM S. McGlynn reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 110806.263 at 06:19:00.58 UT on 6 August 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12255 SUBJECT: Fermi GBM detection of a SGR-like burst DATE: 11/08/08 01:47:36 GMT FROM: Sylvain Guiriec at UAH Sylvain Guiriec (UAH), C. Kouveliotou (NASA/MSFC) and A.J. van der Horst (USRA) report on behalf of the Fermi/GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggered at 23:16:24.91 UT on 7 August 2011 (trigger 334451786 / 110807970) on an SGR-like event,  possibly associated with the source identified earlier by the Swift team  as a new SGR (D'Elia et al. GCN 12253). The on-ground location, using the GBM trigger data, is RA = 279.0, Dec = -5.9 (J2000 degrees, equivalent to 18h36m, -5h52m),  with an uncertainty of 6.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is  currently estimated to be 2 to 3 degrees). The angle from the LAT boresight is 72 degrees. The duration of this event is ~0.1s with little emission beyond 100 keV,  which is typical of SGR bursts. This location is consistent with  the burst detected ~3.3 hours earlier with Swift  (D'Elia et al. GCN 12253), strongly suggesting that the GBM burst  may originate from the same source. However, since this is a very  crowded region which includes 8 SGR sources already, we cannot exclude  as the origin of this event any of the other SGRs, given the large GBM  error box. The results presented above are preliminary. Further follow up observations  are strongly encouraged. " //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12259 SUBJECT: Swift SGR 1834.9-0846: Swift-BAT refined analysis DATE: 11/08/08 11:40:09 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+963 sec from recent telemetry downlinks, we report further analysis of Swift SGR 1834.9-0846 (trigger #458907) (which we reported as GRB 110807A in D'Elia, et al., GCN Circ. 12253). The BAT ground-calculated position is RA, Dec = 278.709, -8.758 deg, which is RA(J2000) = 18h 34m 50.1s Dec(J2000) = -08d 45' 28.4" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows a single spike starting at T_zero and ending at ~T+0.04 sec. T90 (15-350 keV) is 0.032 +- 0.008 sec (estimated error including systematics). The time-averaged spectrum from T+0.0 to T+0.040 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.70 +- 2.57, and Epeak of 40.5 +- 8.0 keV (chi squared 51.9 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.2 +- 0.3 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.48 sec in the 15-150 keV band is 0.3 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.13 +- 0.30 (chi squared 59.7 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. Given the soft nature of this event, the Fermi-GBM event consistant with this location (Guiriec, 12255), and that the Swift location does not match any of the known SGRs, we classify this event as a new SGR source. The digits in the name are derived from the Swift-XRT location (Circ 12253). The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/458907/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12260 SUBJECT: SGR J1834.9-0846: A Neutron Star in W41? DATE: 11/08/08 14:13:26 GMT FROM: Jules Halpern at Columbia U. GRB 110807A/SGR J1834.9-0846 (D'Elia et al., GCN 12253; Guiriec et al., GCN 12255; Barthelmy et al., GCN 12259) is superposed on the supernova remnant W41 (G23.3-0.3), a location that has been well studied by XMM (Tian et al. 2007, ApJ, 657, L25; Mukherjee et al. 2009, ApJ, 691, 1707) and Chandra (Misanovic et al. 2011, ApJ, 735, 33). W41 is also coincident with the high-energy sources HESS J1834-087 and 2FGL J1834.3-0848. Leahy & Tian (2008, AJ, 135, 167) derived a kinematic distance of 3.9-4.5 kpc to W41. Swift XRT quicklook data beginning 6.7 minutes after the trigger shows an absorbed source with an initial 2-10 keV flux of ~1 count/s, declining to a plateau of 0.16 counts/s during 1547 s of exposure spanning 1.5 hr. No significant periodicity is present in this PC mode data for periods longer than 2.5 s with a pulsed fraction limit of ~35%. Due to the small number of counts (~330) and low time resolution, this is not very constraining of an SGR. There is another neutron star candidate, XMMU J183435.3-084443/ CXOU J183434.9-084443, that lies 4.4 arcmin from the Swift XRT source counterpart of SGR J1834.9-0846. Also, the source cataloged as 2XMM J183452.4-084603, which is 6.6 arcsec from the Swift XRT position as noted by D'Elia et al., is not a point source, but rather a patch of diffuse emission. There is no obvious X-ray point source in archival XMM or Chandra images at the Swift XRT location of the SGR. See the above references for further details. In addition, the radio pulsar PSR J1833-0827, which lies 24' north of W41, has a characteristic age of 1.5x10^5 yr and a proper motion of 33 mas/yr away from W41 (Hobbs et al. 2005, MNRAS, 360, 974). It has been considered by several authors as possibly originating in W41. In summary, GRB 110807A/SGR J1834.9-0846 can be considered a third candidate for a neutron star that could be associated with W41. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12263 SUBJECT: Swift Trigger 458942 is probably not a burst DATE: 11/08/08 18:13:08 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), S. T. Holland (CRESST/USRA/GSFC), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. A. Pritchard (PSU), P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/IASFPA) and G. Stratta (ASDC) report on behalf of the Swift Team: At 17:37:46 UT, the Swift Burst Alert Telescope (BAT) triggered on what is probably noise while entering the SAA. This is probably not a GRB or anything astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12265 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 110809.346 is not a GRB DATE: 11/08/09 15:36:29 GMT FROM: Arne Rau at MPE Arne Rau reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 110809.346 at 08:17:41.63 UT on 9 August 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12267 SUBJECT: RXTE Discovery of the Spin Period of Swift J1834.9-0846 DATE: 11/08/10 13:21:45 GMT FROM: Chryssa Kouveliotou at MSFC Ersin Gogus (Sabanci Univ. Istanbul) and Chryssa Kouveliotou (NASA/MSFC) report on behalf of a larger team: RXTE/PCA observed the new source, Swift J1834.9-0846 (D'Elia et al. GCN Circ. 12253, Guiriec et al. 12255) on 2011 August 9-10, for a net exposure time of 9.7 ks. We performed a timing analysis using the barycentered photon arrival times in the 2-10 keV band and detected a coherent pulsation at 0.402853(2) Hz which corresponds to a spin period of 2.482295 s. Note that an earlier PCA observation on 2011 August 9 of the same field with a 3.4 ks exposure did not reveal the pulsed signal clearly but it does confirm the signal at a consistent frequency. The pulse profile shows a broad structure covering about 50% of the spin phase with an evidence of a less significant and shorter second structure. This is the only pulsed signal detected within the 1 degree RXTE field of view. To confirm the association of this pulsar with Swift J1834.9-0846, we also analyzed the Swift/XRT data. We see the signal at the same frequency in the XRT observation of 2011 August 9, but at lower significance. The association of the RXTE pulsar with Swift J1834.9-0846 thus needs to be unambiguously confirmed with further longer XRT exposures or with other low-background X-ray instruments, such as Chandra. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12268 SUBJECT: A new photometric resource for GRB observers DATE: 11/08/10 20:41:55 GMT FROM: Arne A. Henden at AAVSO The AAVSO is conducting the AAVSO Photometric All-Sky Survey (APASS), a public multi-year project to calibrate the entire night sky from 10 P.A. Evans & J.P. Osborne (U. Leicester) report, Following the revision to the enhanced XRT GRB positions (GCN 12250), those for GRBs between 2005 July and 2006 April only were found to be have been degraded in the Aug 5 reprocessing. This was due to the use of an inappropriate alignment calibration file in the standard pipeline processing for this interval. We have now recalculated the positions with the correct files, see http://www.swift.ac.uk/reprocessed.php for details. We thank Daniele Malesani for alerting us and providing additional optical positions to enable improved calibration and testing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12302 SUBJECT: Swift J1834.9-0846: Precise X-ray Position and the Confirmation of its Spin Period DATE: 11/08/23 12:13:05 GMT FROM: Ersin Gogus at Sabanci U/Turkey Ersin Gogus (Sabanci Univ. Istanbul), Chryssa Kouveliotou (NASA/MSFC), Oleg Kargaltsev (FSU), George Pavlov (PSU) report on behalf of a larger collaboration: Swift J1834.9-0846 (D'Elia et al. GCN Circ. 12253, Guiriec et al. 12255) was observed with Chandra/ACIS-S on 2011 August 22 for a 13 ks net exposure time. The timing analysis of the barycentered data in the 0.5-8 keV range clearly reveal the coherent signal at 0.40285032 Hz that is consistent with our earlier report (Gogus et al. ATel 2542) and confirms it as the spin frequency of the new source. We also obtained the accurate X-ray position of the source using wavdetect utility of CIAO 4.4 as RA=18 34 52.12, Dec=-08 45 55.97 with 0.60" positional uncertainty (90% containment). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12303 SUBJECT: Fermi GBM trigger 110823.518 is not a GRB DATE: 11/08/23 14:39:50 GMT FROM: Sinead McGlynn at Excellence Cluster/TUM S. McGlynn (TUM/MPE) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 335795147 (110823518) at 12:25:45.68 UT on 23 August 2011, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12304 SUBJECT: Swift-BAT refined analysis of SFXT IGR J08408-4503 (trigger 501368) DATE: 11/08/25 12:58:07 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+2700 sec from recent telemetry downlinks, we report further analysis of BAT trigger #501368 on SFXT IGR J08408-4503. The BAT ground-calculated position is RA, Dec = 130.189, -45.120 deg, which is RA(J2000) = 08h 40m 45.5s Dec(J2000) = -45d 07' 13.2" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 61%. The mask-weighted light curve shows emission from this source when the position came in to the BAT FoV during a planned slew at T-120 sec. The flux showed a mostly linear decay to half the initial observed value out to ~T+900 sec when it started to increase, peaking at ~T+1500 sec, and returning to zero around T+2500 sec. Any activity beyond this time is not known at this time. The time-averaged spectrum from T+0.0 to T+64.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.56 +- 0.50. The fluence in the 15-150 keV band is 2.9 +- 0.9 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.1 +- 0.0 ph/cm2/sec. The emission was soft throughout the 2700 sec of BAT observations. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/501368/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12305 SUBJECT: Swift-BAT Trigger 501485 is noise DATE: 11/08/26 09:06:44 GMT FROM: Scott Barthelmy at NASA/GSFC B.-B. Zhang (PSU), S. D. Barthelmy (GSFC), V. D'Elia (ASDC), C. Gronwall (PSU), P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 08:30:08 UT, the Swift Burst Alert Telescope (BAT) triggered on noise (trigger=501485). Swift slewed immediately. The BAT on-board calculated location is RA, Dec 264.165, -27.375, which is RA(J2000) = 17h 36m 40s Dec(J2000) = -27d 22' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows nothing significant as is typical for an image trigger. The XRT began observing the field at 08:32:04.8 UT, 116.1 seconds after the BAT trigger. No source was detected in 1.2 ks of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 119 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain extinction expected. Due to the marginal significance of the detection, the lack of an XRT source, the poor positional match with any known gamma-ray source, and the increase in the noise level caused by Sco X-1 and other galactic center sources in the Field of View, we believe that this trigger was probably a noise fluctuation. Burst Advocate for this burst is B.-B. Zhang (bbzhang AT psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12316 SUBJECT: Swift detection of an SGR burst from Swift J1834.9-0846 DATE: 11/08/30 00:08:52 GMT FROM: David Palmer at LANL E. A. Hoversten (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), D. Grupe (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), D. M. Palmer (LANL), C. J. Saxton (UCL-MSSL), C. A. Swenson (PSU), E. Troja (NASA/GSFC/ORAU), C. A. Wolf (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 23:41:12 UT, the Swift Burst Alert Telescope (BAT) triggered on Swift J1834.9-0846 (trigger=501752). Swift will have a delayed slew due to the Earth limb. The BAT on-board calculated location is RA, Dec 278.721, -8.751 which is RA(J2000) = 18h 34m 53s Dec(J2000) = -08d 45' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is less than 1 arcmin from the position of Swift J1834.9-0846. BAT has detected this source several times since August 7, 2011 (D'Elia et al. GCN Circ #12253). The BAT light curve showed a single short soft peak with a duration of about 0.016 sec. The peak count rate was ~3200 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+45.7 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is E. A. Hoversten (hoversten AT astro.psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12317 SUBJECT: SGR Swift J1834.9-0846: Swift-BAT refined analysis of trigger 501752 DATE: 11/08/30 13:16:15 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of SGR Swift J1834.9-0846 (BAT trigger #501752) (Hoversten, et al., GCN Circ. 12316). The BAT ground-calculated position is RA, Dec = 278.710, -8.770 deg, which is RA(J2000) = 18h 34m 50.3s Dec(J2000) = -08d 46' 11.8" with an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 57%. The mask-weighted light curve shows a single spike with a width of ~0.016 sec T90 (15-350 keV) is 0.012 +- 0.001 sec (estimated error including systematics). The time-averaged spectrum from T+0.000 to T+0.012 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 3.15 +- 0.63. The fluence in the 15-150 keV band is 2.8 +- 1.2 x 10^-9 erg/cm2. The 1-sec peak photon flux measured from T-0.49 sec in the 15-150 keV band is 0.34 +- 0.18 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/501752/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12319 SUBJECT: Trigger 502024: Swift detection of KS 1741-293 DATE: 11/09/01 12:44:02 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. Campana (INAF-OAB), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), B. Gendre (ASDC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. J. Mountford (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 12:07:22 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from what we tentatively associate with KS 1741-293 (aka M 1741-293 and AX J1744.8-2921) (trigger=502024). Swift did not slew immediately because the on-board merit system gives these sources a low merit value. The BAT on-board calculated location is RA, Dec 266.252, -29.346, which is RA(J2000) = 17h 45m 00s Dec(J2000) = -29d 20' 45" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single weak peak with a duration of about 10 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 12:31:49.6 UT, 1467.2 seconds after the BAT trigger. No source was detected in 117 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. Although the BAT position is consistent with the LMXRB KS 1741-293, this an extremely crowded field near the Galactic center, so it is possible that the burst came from another Galactic source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12320 SUBJECT: SGR Swift J1834.9-0846: Correction to the Swift-BAT refined spectral analysis DATE: 11/09/01 18:02:58 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) and T. Sakamoto (GSFC/UMBC), (on behalf of the Swift-BAT team): Due to an error in the automated processing, an incorrect best-fit model was selected in Circ 12317. The correct best fit model is the simple blackbody model. We apologise for this error. The time-averaged spectrum from T+0.000 to T+0.012 sec of the event from SGR Swift J1834.9-0846 (BAT Trigger 501752) is best fit by a blackbody model. The blackbody temperature is 9.2 -1.6,+1.4 keV. The fluence in the 15-150 keV band is 5.6 +- 2.6 x 10^-9 erg/cm2. The 1-sec peak photon flux measured from T-0.49 sec in the 15-150 keV band is 0.31 +- 0.19 ph/cm2/sec. All the quoted errors are at the 90% confidence level. We thank A.Kann for bringing this fitting choice error to our attention. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12359 SUBJECT: Swift detection of short bursts from PSR J1647-4552 DATE: 11/09/19 21:39:00 GMT FROM: David Burrows at PSU/Swift W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/IASFPA), E. Sonbas (GSFC/USRA/Adiyaman Univ.) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 21:16:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located PSR J1647-4552 (trigger=503525). Swift slewed immediately to the position. Approximately ten minutes later (21:25:44 UT), BAT triggered again on same position (trigger=503526). The first BAT on-board calculated location is RA, Dec 251.752, -45.843 which is RA(J2000) = 16h 47m 00s Dec(J2000) = -45d 50' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve of the first trigger (503525) showed a single-peaked structure with a duration of about 0.25 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. The second burst had a similar burst intensity and time profile. The XRT began observing the field at 21:17:07.5 UT, 56.0 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 251.79387, -45.87095 which is equivalent to: RA(J2000) = 16h 47m 10.53s Dec(J2000) = -45d 52' 15.4" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 145 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.5 arcseconds from that of a known X-ray source: CXOU J164710.2-455216/PSR J1647-4552, a known magnetar (e.g. Woods et al., 2011, ApJ, 726, 37). A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.88 x 10^22 cm^-2, Kalberla et al. 2005), with an excess column of 2.5 (+2.00/-1.60) x 10^22 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 60 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. No correction has been made for the large, but uncertain extinction expected. It appears that this PSR is entering an SGR-like phase of activity. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12360 SUBJECT: MAXI/GSC detection of a short soft X-ray transient DATE: 11/09/20 09:39:23 GMT FROM: Motoko Suzuki at RIKEN M. Kohama(JAXA), T. Toizumi(Tokyo Tech), H. Negoro (Nihon U.), M. Serino(RIKEN), S. Ueno, H. Tomida, M. Ishikawa (JAXA), M. Matsuoka ,T. Mihara, M. Sugizaki, S. Nakahira, T. Yamamoto, T. Sootome (RIKEN), N. Kawai, M. Morii, K. Sugimori, R. Usui (Tokyo Tech), A. Yoshida, K. Yamaoka (AGU), H. Tsunemi, M. Kimura, H. Kitayama (Osaka U.), M. Nakajima, F. Suwa (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu (Kyoto U.), Y. Tsuboi, T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team: MAXI/GSC triggered at UT 2011-09-16T20:33:01 on a bright uncatalogued soft X-ray transient source. The best-fit position of the source is (R.A., Dec) = (+171.57 deg, -17.71 deg) = (11 26 16, -17 42 22)(J2000) Since the emission was detected only for a fraction of the triangular transit response, the uncertainty of its position along the scan direction is large. Without assuming the source constancy, we obtain a rectangular error box (90%C.L.) with the following corners: (R.A., Dec) = (+170.94 deg, -17.43 deg) = (11 23 45, -17 25 47)(J2000) (R.A., Dec) = (+171.14 deg, -17.18 deg) = (11 24 34, -17 10 35)(J2000) (R.A., Dec) = (+172.19 deg, -18.00 deg) = (11 28 46, -17 59 51)(J2000) (R.A., Dec) = (+171.98 deg, -18.24 deg) = (11 27 55, -18 14 37)(J2000) The preliminary flux (4-10 keV) of the source is approximately 150 mCrab. There was no significant detection at this position in the previous and the following transits (92 min before and after the detection) with an upper limit of 20 mCrab. There is no known bright source at the detected position. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12392 SUBJECT: Swift-BAT trigger 503926 is noise DATE: 11/09/24 16:05:45 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), D. Burrows (PSU), J. R. Cummings (GSFC/UMBC), E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), S. Oates (UCL-MSSL), C Pagani (UL) (for the Swift team): Using the BAT data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of Swift-BAT trigger #503926 (Hoversten, et al., GCN Circ. 12391). This trigger is due to chance coincidence of noise fluctuations in the rate and image domains. XRT observations in Photon Counting mode data started 126 s after the  BAT trigger. In 2ks of PC data no source is detected inside the BAT error circle.  The three sigma upper limit is 4e-3 counts/second. This trigger is a noise event, and is not anything astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12393 SUBJECT: Fermi GBM triggers 110923481, 110924391 and 110925200 are not GRBs DATE: 11/09/26 15:30:37 GMT FROM: Suzanne Foley at MPE S. Foley (MPE) and S. Xiong (UAH) report on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers 338548960 (110924391) at 09:22:38.40 UT on 24 September 2011 and 338618869 (110925200) at 04:47:47.46 UT on 25 September 2011, tentatively classified as GRBs, are in fact due to solar flares. Trigger 338470366 (110923481) at 11:32:44.46 UT on 23 September 2011 is too weak to classify reliably." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12405 SUBJECT: Trigger 504307: Swift detection of MAXI J1836-194 DATE: 11/09/28 19:49:15 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), D. Grupe (PSU), S. T. Holland (CRESST/USRA/GSFC), S. Immler (CRESST/GSFC/UMD), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), C. A. Swenson (PSU), T. N. Ukwatta (MSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 19:17:20 UT, the Swift Burst Alert Telescope (BAT) triggered on MAXI J1836-194 (trigger=504307). The BAT on-board calculated location is RA, Dec 278.950, -19.328 which is RA(J2000) = 18h 35m 48s Dec(J2000) = -19d 19' 40" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This position lies 70 arcseconds from the reported Swift/XRT position of MAXI J1836-194 (Kennea et al., ATEL #3613). The BAT trigger was a 1024s image trigger. As is usual for an image trigger, the BAT light curve shows nothing of note. Due to an observing constraint, Swift will not slew until T0+47.2 minutes. There will be no XRT or UVOT data until this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12513 SUBJECT: All GCN Circulars available in a tarfile for data mining DATE: 11/10/30 18:37:59 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) All the GCN Circulars (12,500+) are now available in a tarfile. This single file is convenient if you want to 'mine' the Circulars for information. The tarfile is updated 1 or 2 minutes after midnight US_East_Coast time every day. The link is near the bottom of the main Circulars archive page. http://gcn.gsfc.nasa.gov/gcn3/all_gcn_circulars.tar //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12517 SUBJECT: Swift-BAT trigger 506884 is not a GRB DATE: 11/11/03 04:20:54 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), E. A. Hoversten (PSU), F. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU) and M. C. Stroh (PSU) report on behalf of the Swift Team: At 03:28:08 UT 03 Nov 2011, Swift-BAT triggered as a result of the star tracker having lost lock. This trigger is not due to a GRB or anything astrophysical. Only one GCN Notice type (the Quick_Look type that goes to robotic telescopes) was distributed to the world. All the rest of the notice types were automatically blocked-to-world for Image triggers that occur during a period of star tracker loss-of-lock. But the Quick-Look notice is produced before any information is received that it is an Image trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12522 SUBJECT: Trigger 506913: Swift detection of Swift J1922.7-1716 and its optical counterpart DATE: 11/11/03 14:37:59 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester), D. Grupe (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/IASFPA), E. Sonbas (GSFC/USRA/Adiyaman Univ.), R. L. C. Starling (U Leicester), C. A. Swenson (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 14:12:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located an event from the known source Swift J1922.7-1716 (trigger=506913). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 290.667, -17.284 which is RA(J2000) = 19h 22m 40s Dec(J2000) = -17d 17' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiple-peaked structure with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~4 sec after the trigger. The XRT began observing the field at 14:14:23.4 UT, 130.2 seconds after the BAT trigger. XRT found a bright, X-ray source located at RA, Dec 290.6533, -17.2835 which is equivalent to: RA(J2000) = 19h 22m 36.79s Dec(J2000) = -17d 17' 00.6" with an uncertainty of 5.3 arcseconds (radius, 90% containment). This location is 47 arcseconds from the BAT onboard position, within the BAT error circle, and 3.6 arc seconds from the position of Swift J1922.7-1716 reported by Tueller et al. (ATEL #669). No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 150 seconds with the White filter starting 140 seconds after the BAT trigger. There is a candidate optical counterpart in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 19:22:37.00 = 290.65415 DEC(J2000) = -17:17:01.1 = -17.28363 with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.0 arc sec. from the center of the XRT error circle. This counterpart is not observed in archival DSS imaging. The estimated magnitude is 16.67 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.12. This source, Swift J1922.7-1716, (Tueller et al., 2005, ATEL #669; Falanga et al., 2006, A&A v456 pL5), is currently in outburst (Nakahira et al., 2011 ATEL #3548; Kennea et al., 2011 #3567) and has been slowly rising for the past few months. ( http://swift.gsfc.nasa.gov/docs/swift/results/transients/SWIFTJ1922.7-1716/ ) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12526 SUBJECT: Trigger 506913: MASTER detection of Swift J1922.7-1716 optical counterpart DATE: 11/11/03 17:01:31 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina,N.Shatskiy, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev,E.Konstantinov, Irkutsk State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnich, A. Popov Ural State University, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located near Kislovdsk was pointed to the Trigger 506913: Swift J1922.7-1716 (Barthelmy et al., GCN Circ 12522) 28 s after notice time and 98 sec after Trigger time. Unfortunately our first 10s exposure set in two polarizations are saturated by evening sky light. The preliminary photometry of the first unsaturated images gives: UT T-T_trig mag 2011-11-03 14:55:24 2385s 17.4 +-0.3 Observations and data reduction are continuated. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12554 SUBJECT: XRF 111111A/MAXI J0158-744: MAXI GSC and SSC detection of a soft X-ray transient near SMC DATE: 11/11/11 09:18:05 GMT FROM: Nobuyuki Kawai at Tokyo Tech M. Kimura (Osaka U.), H. Tomida (JAXA), T. Sootome, M. Serino, T. Mihara,(RIKEN), M. Morii (Tokyo Tech), M. Matsuoka, M. Sugizaki, S. Nakahira, T. Yamamoto (RIKEN), S. Ueno, M. Kohama, M. Ishikawa (JAXA), N. Kawai, K. Sugimori, R. Usui, T. Toizumi, Y. Aoki, S. Song (Tokyo Tech), A. Yoshida, K. Yamaoka (AGU), H. Tsunemi, H. Kitayama (Osaka U.), H. Negoro, M. Nakajima, F. Suwa (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu (Kyoto U.), Y. Tsuboi, T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team MAXI/GSC triggered a bright uncatalogued X-ray transient source at UT 2011-11-11T05:05:59. The source is extremely soft and most of the flux is emitted below 4keV. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (+29.5 deg, -74.4 deg) = (01 58 03, -74 24 01)(J2000) with a 90% C.L. statistical error of 0.42 deg. There is additional systematic uncertainty of 0.1 deg (90% containment radius). This position is in the outskirts of SMC. The preliminary flux of the transient source was 400 mCrab (2-4 keV), and that corresponds to the luminosity of 6.4e38 erg s-1 (distance of SMC 61.3kpc is assumed). The hardness ratio gives the blackbody temperature of about 0.4 keV. This source is also detected by SSC with the flux of 1 Crab (0.7-7 keV). There was no significant detection at the transit location in the previous and the next orbit (92 min before and after the detection) with an upper limit of 20 mCrab. There is no known bright X-ray source at the detected position. There are at least four super soft sources known in SMC, and any of them does not match this transient. Follow-up observations are encouraged. This message has been cross-posted to ATel. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12555 SUBJECT: XRF 111111A/MAXI J0158-744: MAXI GSC refined analysis DATE: 11/11/11 16:50:54 GMT FROM: Nobuyuki Kawai at Tokyo Tech M. Morii (Tokyo Tech), M. Kimura (Osaka U.), H. Tomida (JAXA), T. Sootome, M. Serino, T. Mihara,(RIKEN), M. Matsuoka, M. Sugizaki, S. Nakahira, T. Yamamoto (RIKEN), S. Ueno, M. Kohama, M. Ishikawa (JAXA), N. Kawai, K. Sugimori, R. Usui, T. Toizumi, Y. Aoki, S. Song (Tokyo Tech), A. Yoshida, K. Yamaoka (AGU), H. Tsunemi, H. Kitayama (Osaka U.), H. Negoro, M. Nakajima, F. Suwa (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu (Kyoto U.), Y. Tsuboi, T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team The error region of XRF 111111A / MAXI J0158-744 (ATEL #3756) is refined by further analysis. We obtain a statistical 90% C.L. elliptical error region centered on (R.A., Dec) = (29.92 deg, -74.11 deg) = (01 59 40, -74 06 50)(J2000) with long and short radii of 0.13 deg and 0.06 deg, respectively. The position angle of long axis is 17.1 deg. There is additional systematic uncertainty of 0.1 deg (90% containment radius). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12709 SUBJECT: XRT GRB Catalogue now live and online DATE: 11/12/20 13:47:33 GMT FROM: Phil Evans at U of Leicester P.A. Evans, J.P. Osborne (U. Leicester), D.N.Burrows (PSU) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift-XRT team: An automatically updated version of the XRT GRB catalogue is now available online at http://www.swift.ac.uk/xrt_live_cat This contains time-resolved analysis of every GRB detected by XRT, and many of the plots from the original XRT catalogue (Evans et al. 2009, MNRAS, 397, 1177), and is automatically updated, with new bursts incorporated once they are 24 hours old (to allow sufficient data to accumulate). For each GRB various plots are shown to allow easy comparison of details such as temporal and spectral decay indices for that specific burst with the population at large. This is a publically-available facility, however we request that users cite Evans et al. (2009). This circular, and the facility, are official products of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12712 SUBJECT: Trigger 510075 is not a GRB DATE: 11/12/21 02:47:35 GMT FROM: David Palmer at LANL W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), D. Grupe (PSU), E. A. Hoversten (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), C. A. Swenson (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 02:14:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 510075. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 91.175, -23.979 which is RA(J2000) = 06h 04m 42s Dec(J2000) = -23d 58' 43" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is potentially confused by the presence of Vela X-1 in the Field of View. Although the on-board significance was strong enough to report a trigger (6.74 sigma), a refined ground analysis produces a significance of 6.0 sigma, which is below the standard BAT triggering threshold. The XRT began observing the field at 02:17:00.1 UT, 132.5 seconds after the BAT trigger. No source was detected in 428 s of promptly downlinked data. UVOT took a finding chart exposure of 150 seconds with the White filter starting 135 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. Due to the low significance in the ground re-analysis of the BAT map and the non-detection by XRT, we believe that this event is not a GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12816 SUBJECT: INTEGRAL Weak trigger #6433: GRT Optical Observation DATE: 12/01/07 00:56:13 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (UMD/GSFC), N. Gehrels (GSFC), T. Okajima (GSFC), Y. Urata (NCU) We observed the field of INTEGRAL Weak trigger #6433 with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). A total 242 good quality images of 5 sec (200 images) and 30 sec (42 images) exposures were taken in the R filter starting from Jan 6 05:11:52 (UT), about 58 seconds after the trigger (53 seconds after the notice), and stopped on Jan 6 06:08:10 (UT). We do not detect the optical afterglow both in the individual images and the stacked image inside the 3.65 arcmin error circle. The estimated five sigma upper limit of the combined image (total exposure of 2260 sec) is ~17.4 mag using the USNO-B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12829 SUBJECT: Swift detection of an SGR burst from AXP 4U 0142+61 DATE: 12/01/12 13:30:31 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), B. Gendre (ASDC), C. Guidorzi (U Ferrara), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), O. M. Littlejohns (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), R. L. C. Starling (U Leicester), G. Stratta (ASDC) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift Team: At 13:09:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from AXP 4U 0142+61 (trigger=511611). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 26.621, +61.763 which is RA(J2000) = 01h 46m 29s Dec(J2000) = +61d 45' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a total duration about 64 millisec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 13:10:56.9 UT, 78.5 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 26.59414, 61.75160 which is equivalent to: RA(J2000) = 01h 46m 22.59s Dec(J2000) = +61d 45' 05.8" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.0 arcseconds from that of a known X-ray source: AXP 4U 0142+61. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 8.13 x 10^21 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 82 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The coverage of the XRT error circle by the 8'x8' region for the list of sources generated on-board is uncertain because the large number of sources filled the available telemetry. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This source has produced previous SGR bursts (most recently last July, Oates et al. GCN 12209) and is part of a regular monitoring program of AXPs (PI: V. Kaspi). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12831 SUBJECT: AXP 4U 0142+61: Swift-BAT refined analysis (trigger 511611) DATE: 12/01/13 00:33:18 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+420 sec from recent telemetry downlinks, we report further analysis of BAT trigger #511611 on AXP 4U 0142+61 (Barthelmy, et al., GCN Circ. 12829). The partial coding was 84%. The mask-weighted light curve shows a single FRED-like peak starting at T_0 and lasting for ~250 msec. T90 (15-350 keV) is 0.024 +- 0.009 sec (estimated error including systematics). The time-averaged spectrum from T+0.008 to T+0.036 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.32 +- 0.50. The fluence in the 15-150 keV band is 6.8 +- 2.1 x 10^-9 erg/cm2. The 1-sec peak photon flux measured from T-0.48 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/511611/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12845 SUBJECT: AXP 4U 1042+61: Mondy optical observations DATE: 12/01/17 18:19:43 GMT FROM: Alina Volnova at SAI MSU A. Volnova (SAI MSU), I. Korobtsev, E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed the field of the AXP 4U 1042+61 (Swift  trigger 511611,Barthelmy et al., GCN 12829) with AZT-33IK telescope of Sayan observatory (Mondy) on Jan., 12 between (UT) 14:11:04 - 15:01:42 with a mean seeing (FWHM) of about 2.1". We took several series of 60 s exposures in R-filter. In a stacked image we do not detect any source in the XRT error circle. The photometry is based on the USNO-B1.0 1517-0055618 star (RA=01 46 21.83, Dec=+61 45 56.9) assuming R2=18.17. UT_start,   t-t0, Filter, Exposure,   OT       uplim               d s                       3 sigma 14:11:04  0.06753 R 50x60       n/d      22.3 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12849 SUBJECT: XRF 120118A: an X-Ray Flash detected by INTEGRAL DATE: 12/01/18 07:39:03 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay), S.Mereghetti (IASF-Milano), J. Borkowski (CAMK, Torun), C.Ferrigno, E.Bozzo, C. Tchernin (ISDC, Versoix), on behalf of the IBAS Localization Team report: a long gamma ray burst lasting about 60 s has been detected by IBAS in the IBIS/ISGRI data at 06:04:44 UT on January 18. Its refined coordinates (J2000) are: RA: 195.403 [degrees] DEC: -61.644 [degrees] with an uncertainty of 2.7 arcmin (90% c.l.). The GRB is detected only in the 20-40 keV energy band. Due to its soft spectrum, we consider this event an XRF. The 20-200 keV fluence is about 2e-7 erg/cmsq, while its peak flux over 5 s in the same energy band is about 0.1 ph/cmsq/s. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12850 SUBJECT: XRF 120118A: further INTEGRAL analysis DATE: 12/01/18 10:24:50 GMT FROM: Diego Gotz at CEA D. Gotz (CEA Saclay) and E. Bozzo (ISDC Versoix) on behalf of the IBAS Localisation Team report: A deeper analysis of an extended IBIS/ISGRI dataset shows that the HMXB GX 304-1 is in an active state. Being this source just 3.4 arc min away from the position derived for XRF120118A (Gotz et al., GCN Circ. 1248), even if not formally compatible with the 90% c.l. error circle of the latter, we note that the chance of XRF120118A being produced by GX 304-1 can not be completely excluded at this stage. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12851 SUBJECT: XRF 120118A: Optical candidate DATE: 12/01/18 14:53:42 GMT FROM: Juan Carlos Tello at IAA-CSIC J.C. Tello (IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC), J. Gorosabel (IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), P. Kubanek (CTU Praha), W. Allen (Vintage Lane Obs, New Zealand), Ph. Yock (Auckland Univ.), Kuan-Yu Lin (Auckland Univ.), report on behalf of a larger collaboration: We observed the field of XRF 120118A (Gotz et al., GCNC 12849), detected by INTEGRAL, with the 0.6m Yock-Allen telescope at the BOOTES-3 station in Blenheim (New Zealand). Unfiltered images were obtained starting on 09:21:00 UT (03h16m after the burst, limited by setting of the Sun) and were combined in two sets of 53x60s of exposure each. We detect a fading source at RA(J2000): 13:01:22.72 (195.344 [degrees]) DEC(J2000): -61:39:23.20 (-61.656 [degrees]) In the first set with a mean observation time of 09:31:06 UT we observe a magnitude of 18.60 (calibrated against USNO-B1 R2 filter). Roughly an hour later it's decayed more than 2 magnitudes. This source is well within the INTEGRAL 2.7 arcmin 90% c.l. and is not observed in catalog USNO-B1 Spectroscopic observations are encouraged. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12855 SUBJECT: XRF 120118A: early optical limit by "Pi of the Sky" DATE: 12/01/18 21:39:20 GMT FROM: Agnieszka Majczyna at Nat.Center for Nuclear Res. T.Batsch,A.Majcher,A.Majczyna,K.Nawrocki,M.Sokolowski,G.Wrochna (NCBJ, Swierk), M.Cwiok,L.W.Piotrowski,A.F.Zarnecki (University of Warsaw), K.Malek,L.Mankiewicz,R.Opiela,M.Siudek,V.Repei (CFT PAN), G.Kasprowicz,M.Zaremba (Warsaw University of Technology), from the "Pi of the Sky" collaboration ( http://grb.fuw.edu.pl ). The wide field "Pi of the Sky South" telescope, installed in the private observatory of Alain Maury in San Pedro de Atacama (http://grb.fuw.edu.pl/pi/index.html#spda_site.htm) observed field of XRF 120118A few minutes before and ~100s after the flash. No new source brighter than about 11.3 mag has been identified on 10s exposures and no source brighter than 11.7 mag on 20 coadded frames: t_start - t0 [s] t_exp start (UT) end (UT) 3-sigma limit -290 10s 06:00:14 06:00:24 11.2 +99 10s 06:06:43 06:06:53 11.3 +129 20x10s 06:07:13 06:12:12 11.7 where limit is based on the reference star magnitudo in V filter. We acknowledge great support received from Alain Maury at SPdA Observatory. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12896 SUBJECT: Fermi GBM trigger 120123.169 is not a GRB DATE: 12/01/23 14:26:29 GMT FROM: David Gruber at MPE D. Gruber (MPE) and V. Connaughton report on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 348984161 (120123169) at 04:02:39.68 UT on 23 January 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12914 SUBJECT: Swift detection of a burst from LS I +61 303 DATE: 12/02/05 12:25:11 GMT FROM: David Palmer at LANL D. N. Burrows (PSU), M. M. Chester (PSU), V. D'Elia (ASDC), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), C. J. Saxton (UCL-MSSL), E. Sonbas (NASA/GSFC/Adiyaman Univ.), M. Stamatikos (OSU/NASA/GSFC) and G. Stratta (ASDC) report on behalf of the Swift Team: At 11:47:24 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst consistent with the known High Mass X-Ray binary LS I +61 303 (trigger=513505). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 40.100, +61.220 which is RA(J2000) = 02h 40m 24s Dec(J2000) = +61d 13' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short spike with a duration of about 64 ms or less. The peak count rate was 1500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 11:48:42.0 UT, 77.5 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 40.1326, 61.2290 which is equivalent to: RA(J2000) = 02h 40m 31.83s Dec(J2000) = +61d 13' 44.4" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.2 arcseconds from that of a known X-ray source: LS I +61 303, and 65.1 arcseconds from the on-board BAT position. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 7.57 x 10^21 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 80 seconds after the BAT trigger, and a finding chart exposure of 250 seconds with the U filter starting 293 seconds after the BAT trigger. A source consistent with the position of LS I +61 303 is detected, with white = 13.8 and u = 12.5 (1-sigma errors of about 0.1.). The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The BAT position is within 1.1 arcminutes of the micro-quasar source LS I +61 303, and the XRT position is consistent in both position and observational characteristics to our previous observations of this source. This location has previously been the source of similar magnetar-like bursts (Torres et al. Astrophys. J., 744, 106 (2012)). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12916 SUBJECT: LS I +61 303: Swift-BAT refined analysis DATE: 12/02/05 20:17:30 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), D. M. Palmer (LANL), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the BAT data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of the outburst from LS I +61 303 (trigger #513505) (Burrows, et al., GCN Circ. 12914). The BAT ground-calculated position is RA, Dec = 40.059, 61.235 deg, which is RA(J2000) = 02h 40m 14.3s Dec(J2000) = +61d 14' 05.9" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 76%. The mask-weighted light curve shows a single, roughly symmetric pulse starting at ~T+0.00 sec and ending at ~T+0.070 sec. T90 (15-350 keV) is 0.040 +- 0.011 sec (estimated error including systematics). The time-averaged spectrum from T+0.020 to T+0.064 sec is best fit by a blackbody model. The blackbody temperature is 5.69 +- 1.22 keV. Chisq is 41.2 with 59 DoF. The fluence in the 15-150 keV band is 8.0 +- 3.2 x 10^-9 erg/cm2. The 1-sec peak photon flux measured from T-0.46 sec in the 15-150 keV band is 0.30 +- 0.19 ph/cm2/sec. A simple power law fit yeilds an index of 3.92 +- 0.24 with a Chisq of 49.4 with 57 DoF. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/513505/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12958 SUBJECT: Fermi GBM detection of an SGR-like burst DATE: 12/02/15 10:19:00 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 09:07:49.67 UT on 07 February 2012, the Fermi Gamma-Ray Burst Monitor triggered on a soft, short event (trigger 350298471 / 120207380). The event was tentatively classified as a solar flare, but it may be a burst from a Galactic source, most likely the soft gamma repeater SGR 1806-20. The on-ground calculated location, using the GBM trigger data, is RA = 270.0, DEC = -24.5 (J2000 degrees, equivalent to 18 h 00 m, -24 d 30 '), with an uncertainty of 3.9 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to Galactic coordinates: Long = 8.9, Lat = -6.9 (J2000 degrees), consistent with the position of SGR 1806-20 and other known SGRs in that region. We conclude that this burst is either coming from one of these sources or from a new, yet unknown source. The angle from the Fermi LAT boresight is 80 degrees. The GBM light curve shows a single peak with a duration of about 150 ms. The time-averaged spectrum from T0-0.032 s to T0+0.096s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.04 +/- 0.31 and the cutoff energy, parameterized as Epeak, is 25.5 +/- 1.2 keV. The event fluence (10-1000 keV) in this time interval is (1.9 +/- 0.1)E-07 erg/cm2. The temporal and spectral analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12975 SUBJECT: GCN 12974 : Errata in the Subject DATE: 12/02/20 15:08:58 GMT FROM: Shashi Bhushan Pandey at ROTSE Brajesh Kumar, Vijay Kumar Bhatt and S. B. Pandey (ARIES, Nainital, India, on behalf of larger Indian GRB collaboration). We made a typo in the subject heading of GCNC 12974. The correct subject would be "GRB 120219A: optical observations". We apologize for the typo. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12985 SUBJECT: Swift Trigger 516027 is CC Eri DATE: 12/02/24 19:35:10 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), O. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), C. J. Mountford (U Leicester), S. R. Oates (UCL-MSSL), P. T. O'Brien (U Leicester), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU), M. Stamatikos (OSU/NASA/GSFC), C. A. Swenson (PSU), G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/ORAU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 19:05:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located emission from the location of the flare star CC Eri (trigger=516027). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 38.526, -43.825 which is RA(J2000) = 02h 34m 06s Dec(J2000) = -43d 49' 30" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for a 5-minute image trigger there is no obvious variation in the immediately available lightcurve. The XRT began observing the field at 19:12:21.5 UT, 397.5 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 38.5956, -43.7978 which is equivalent to: RA(J2000) = +02h 34m 22.94s Dec(J2000) = -43d 47' 52.1" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 205 arcseconds from the BAT onboard position. This position is 5.4 arcseconds from that of a known X-ray source: the flare star, CC Eri. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 7.03e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 27 seconds with the White filter starting 406 seconds after the BAT trigger. This source is very bright, as expected for a flaring star with a quiescent magnitude of V=8.8. More analysis will be required to provide an estimate of the magnitude. The expected extinction corresponds to an E(B-V) of 0.02. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13061 SUBJECT: Fermi GBM triggers 120305.186, 120305.802 and 120306.823 are not GRBs DATE: 12/03/13 16:00:51 GMT FROM: Suzanne Foley at MPE S. Foley (UCD), A. Collazzi (NASA/ORAU) and J. Michael Burgess (UAH) report on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers 352614476 (120305186) at 04:27:54.53 UT on 05 March 2012, 352667687 (120305802) at 19:14:45.62 on 05 March 2012 and 352755934 (120306823) at 19:45:32.24 on 06 March 2012, tentatively classified as GRBs, are in fact not due to GRBs. These triggers are due to solar flares." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13062 SUBJECT: Fermi GBM triggers 120309.265 and 120309.402 are not GRBs DATE: 12/03/13 19:34:15 GMT FROM: David Gruber at MPE D. Gruber (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 352966871 (120309.265) at 06:21:09.42 UT and trigger 352978754 (120309.402) at 09:39:12.33 UT on 09 March 2012, both tentatively classified as a GRB, are in fact not due to GRBs. These triggers are due to precipitating magnetospheric particles caused by solar activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13068 SUBJECT: Trigger 517876 is a Swift detection of GX 5-1 DATE: 12/03/16 12:28:37 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), S. T. Holland (STScI), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), A. Melandri (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 11:50:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GX 5-1 (trigger=517876). Swift did not slew to this source because of the Moon observing constraint. The BAT on-board calculated location is RA, Dec 270.260, -25.087, which is RA(J2000) = 18h 01m 02s Dec(J2000) = -25d 05' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is 0.6 arcmin from the GX 5-1 location. This was a 13-min image trigger, and as typical the TDRSS lightcurve does not show any activity. Because of the Moon observing constraint, there will be no slew and therefore no XRT or UVOT data on this target. We also note that the on-board identification for this trigger went out on the GCN Notices as SAX_J1819.3-252 which is not correct and it did not find the the GX 5-1 entry, and as such this caused a notice to be issued. The correct identification is the ground identification of GX 5-1, and is believed to be in its normal range of variability. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13076 SUBJECT: Fermi GBM trigger 120319.237 is not a GRB DATE: 12/03/20 15:10:19 GMT FROM: Sinead McGlynn at Excellence Cluster/TUM S. McGlynn (TUM/MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 353828472 (120319237) at 05:41:10.25 UT on 19 March 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13078 SUBJECT: GRB 12032A, Swift-BAT refined analysis DATE: 12/03/20 16:10:19 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+512 sec from the recent telemetry downlink, we report further analysis of BAT GRB 120320A (trigger #518200) (Markwardt, et al., GCN Circ. 13071). The BAT ground-calculated position is RA, Dec = 212.517, 8.682 deg which is RA(J2000) = 14h 10m 04.0s Dec(J2000) = +08d 40' 54.9" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%. The mask-weighted light curve shows two overlapping weak peaks. There is possible low-level emission out to approximately T+90 sec. T90 (15-350 keV) is 25.74 +- 3.55 sec (estimated error including systematics). The time-averaged spectrum from T-0.01 to T+29.86 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.31 +- 0.95, and Epeak of 62.8 +- 23.4 keV (chi squared 57.5 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.9 +- 1.6 x 10^-07 erg/cm2 and the 1-sec peak flux measured from T+24.10 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.58 +- 0.18 (chi squared 64.7 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/518200/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13089 SUBJECT: Simultaneous optical images of Swift pointing are available by GRT DATE: 12/03/24 03:22:13 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC), T. Okajima (GSFC) We want to inform that the 14-inch Goddard Robotic Telescope (GRT) has been chasing the Swift pointings starting from December 24, 2012. Our collected data are available at: http://asd.gsfc.nasa.gov/Takanori.Sakamoto/GRT/grt_swift_pointing.html Due to a combination of position of the Swift's pointing and weather at the site, about maximum of 10% of the Swift's fields are simultaneously monitored by the telescope (GRT responds automatically via GCN SWIFT_POINTDIR notice). To be complimentary with the Swift NFI data (especially UVOT), GRT is collecting images in the R filter (fifteen 60-sec exposures for each pointing). The images are calibrated for bias, dark and flat. Only the images with successfully assigned WCS information are available. Since all the data acquisition, reduction and analysis are performed automatically, some images might not be processed property (or might be of a lower quality). The processed images observed at the previous night will be available on the above webpage around 16 UT that day. If you use GRT data for your publication, please reference the GRT paper: Sakamoto et al. 2011, Advances in Space Research 47, 1444-1450 We are hoping that our additional optical images will be useful to the community to enhance the science outputs using the Swift data. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13105 SUBJECT: grb 654321: test DATE: 12/03/25 23:10:20 GMT FROM: Scott Barthelmy at NASA/GSFC this is a test. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13166 SUBJECT: Trigger 518853: Swift detection of a probable Galactic transient DATE: 12/03/29 03:15:17 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), C. A. Swenson (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 02:22:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located emission from an unknown source (trigger=518853). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 188.528, -63.420 which is RA(J2000) = 12h 34m 07s Dec(J2000) = -63d 25' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is not immediately available, but the source was detected by its emission over a 12 minute image trigger. The XRT began observing the field at 02:37:30.0 UT, 922.1 seconds after the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located at RA, Dec 188.5114, -63.4011 which is equivalent to: RA(J2000) = +12h 34m 2.74s Dec(J2000) = -63d 24' 04.0" with an uncertainty of 5.0 arcseconds (radius, 90% containment). No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 2.50e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the U filter starting 927 seconds after the BAT trigger. No uncatalogued source has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the large, but uncertain extinction expected. UVOT does detect a known optical DSS source within 3.6 arcseconds of the XRT position. This source was originally identified by the onboard software as IGR12349-6434, but the XRT location is positionally inconsistent with that source. There are no known high-energy sources at the measured location. Due to the long duration of the detection interval, the sustained high intensity of the XRT measurement, and the proximity of the source to the Galactic plane, we believe that this source is likely to be due to a previously unknown Galactic transient. However, we cannot rule out the possibility of a GRB with the currently available data. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13167 SUBJECT: The Swift-XRT source associated with trigger 518853 is a cosmic ray DATE: 12/03/29 08:52:28 GMT FROM: Phil Evans at U of Leicester P.A. Evans and J.P. Osborne (U. Leicester) reports on behalf of the Swift-XRT team: Further analysis of the Swift-BAT trigger #518853 (Barthelmy et al., GCN 13166) reveals that the XRT object referred to in GCN 13166 is a cosmic ray, rather than an astrophysical X-ray source. In 2 ks of Photon Counting mode data, we find no evidence for any X-ray sources in the BAT error circle, to a 3-sigma upper limit of 0.004 counts s^1. One of the reasons for doubting the initial classification of the trigger as IGR12349-6434 is therefore removed. We apologise for any confusion. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13168 SUBJECT: Swift trigger 518853: MASTER-ICATE possible OT DATE: 12/03/29 12:37:09 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Kuznetsov, A.Sankovich Moscow Lomonosov State University, Sternberg Astronomical Institute, K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University MASTER-ICATE robotic Very Wide Field (http://93.180.27.230:8080/) located in Argentina was pointed to the area of the Trigger 518853 (Barthelmy et al., GCN Circ 13166) several minutes before notice time (due to Swiwt pointing info) and 12.9 min after GRB time at 2012-03-29 02:34:16.391. We find OT with Mag= 13.2 (unfiltered red CCD) at Ra=188.552513 Dec -63.417673 Ra 12:34:12.60 Dec -63:25:03.62 With 25" sec 3-sigma error box. Thre is 2MASS nonstar object 12340720-6325129 with 1.2 arcsec offset. That is inside XRT error box. The absence OT in UVOT data may be connected with very high reddening of the source by Galactic extinction and distinction in time observations. The follow up IR observations are requied to chose between CR or High Energy Transient nature (Evans and Osborne, GCN Circ 13167) of the event. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13173 SUBJECT: Swift trigger 518853 is most likely GX 301-2 DATE: 12/03/29 18:24:14 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) and T. Sakamoto (GSFC/UMBC) on behalf of the Swift team: Swift trigger 518853 (reported in GCN 13166) is not due to a new galactic transient, nor is it a GRB. This trigger was the result of a large roll angle error and an on-board misidentification of GX 301-2 as IGR12349-6434. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13237 SUBJECT: Trigger 519868: Swift detection of SGR1806-20 DATE: 12/04/10 23:23:06 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), E. A. Hoversten (PSU), C. B. Markwardt (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 23:08:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from SGR1806-20 (trigger=519868). Swift did not slew because of the Moon observering constraint. The BAT on-board calculated location is RA, Dec 272.153, -20.410 which is RA(J2000) = 18h 08m 37s Dec(J2000) = -20d 24' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 0.2 sec. The peak count rate was ~13,000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint Swift will be unable to observe this field with the XRT and UVOT instruments until 12 April at 14:00 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13238 SUBJECT: Swift Trigger 519874 is probably a noise event DATE: 12/04/11 01:31:44 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), D. N. Burrows (PSU), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), E. A. Hoversten (PSU), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), C. A. Swenson (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 01:16:39 UT, the Swift Burst Alert Telescope (BAT) triggered and located a marginal peak (6.51 sigma) in the resulting image (trigger=519874). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 35.550, +59.746 which is RA(J2000) = 02h 22m 12s Dec(J2000) = +59d 44' 46" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows nothing significant at the time of the trigger. The XRT began observing the field at 01:18:11.4 UT, 92.5 seconds after the BAT trigger. No source was detected in 218 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 95 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. Due to the marginal nature of the BAT detection, and the lack of any detection by XRT and UVOT despite the prompt slew, we believe that this event was most likely a statistical fluctuation and not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13239 SUBJECT: SGR1806-20, Swift-BAT refined analysis (Trigger 519868) DATE: 12/04/11 12:36:01 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of the outburst from SGR1806-20 (trigger #519868) (Barthelmy, et al., GCN Circ. 13237). The BAT ground-calculated position is RA, Dec = 272.163, -20.405 deg, which is RA(J2000) = 18h 08m 39.1s Dec(J2000) = -20d 24' 19.0" with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 16%. The mask-weighted light curve shows a single spike starting at ~T-0.002 sec, peaking at ~T+0.003 sec, and ending at ~T+0.15 sec with a tail out to ~T+0.4 sec. T90 (15-350 keV) is 0.77 +- 0.32 sec (estimated error including systematics). The time-averaged spectrum from T-0.06 to T+0.96 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.77 +- 0.15. The fluence in the 15-150 keV band is 5.1 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band is 10.7 +- 0.9 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/519868/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13240 SUBJECT: Swift Trigger 519874 is a noise event DATE: 12/04/11 13:02:05 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) on behalf of the Swift-BAT team: Using the data set from T-60 to T+243 sec from recent telemetry downlinks, we confirm that BAT trigger 519874 (Barthelmy, et al., GCN Circ. 13238) is due to noise in the BAT detector (specifically a cosmic ray shower in the instrument). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13262 SUBJECT: Swift Trigger 520928 is probably not a burst DATE: 12/04/26 12:01:18 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), M. M. Chester (PSU), P. A. Evans (U Leicester), B. Gendre (ASDC), C. Guidorzi (U Ferrara), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), O. M. Littlejohns (U Leicester), A. Maselli (INAF-IASFPA), P. T. O'Brien (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 11:38:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located a potential source which could be a GRB (trigger=520928). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 75.720, -26.314 which is RA(J2000) = 05h 02m 53s Dec(J2000) = -26d 18' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the currently available BAT light curve does not show much structure. The XRT began observing the field at 11:40:56.3 UT, 160.5 seconds after the BAT trigger. No source was detected in 300 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. No UVOT processed data products are available at this time. Due to the marginal detection (7.05 sigma) in the image, the lack of a detectable rate increase, and the non-detection by XRT and UVOT despite the prompt slew, it is likely that this is merely a statistical fluctuation and not an astrophysical source. However, the immediately available XRT data covers only 70% of the BAT error circle. A definitive determination of the reality of the source will require the download of the full dataset. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13264 SUBJECT: Swift Trigger 520928 is a noise event DATE: 12/04/26 16:00:51 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy and H.A. Krimm (GSFC) on behalf of the Swift-BAT team: Using the data set from T-60 to T+243 sec from recent telemetry downlinks, we confirm that BAT trigger 520928 (Barthelmy, et al., GCN Circ. 13262) is due to positive noise fluctuation in the BAT image. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13266 SUBJECT: Konus-Wind observation of GRB DATE: 12/04/27 16:26:02 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The bright GRB 120426A (IPN localization: Hurley at al., GCN 13265) triggered Konus-Wind at T0=07755.610s UT (02:09:15.610) The light curve shows a broad pulse with a total duration of ~3.2 s. The emission is seen up to ~8 MeV and displays a noticeable hard-to-soft spectral evolution. A spectral lag between the hard G3(1400-300 keV) and the soft G1(25-90 keV) instrument's light curves is estimated to 0.57 ± 0.8 s (1 sigma). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB120426_T07755/ As observed by Konus-Wind the burst had a fluence of (1.9 ± 0.1)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.344 s, of (1.3 ± 0.2)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+2.048 s) is best fitted in the 20 keV - 10 MeV range with the GRB (Band) model, for which: the low-energy photon index alpha = -0.61 (-0.10, +0.11), the high energy photon index beta = -3.2 (-0.4, +0.2), the peak energy Ep = 140(-8, +7) keV, chi2 = 84.8/81 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13270 SUBJECT: Swift detection of 4U 1630-47 DATE: 12/04/28 16:35:47 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), M. H. Siegel (PSU), E. Sonbas (NASA/GSFC/Adiyaman Univ.), M. Stamatikos (OSU/NASA/GSFC), M. C. Stroh (PSU), C. A. Swenson (PSU), G. Tagliaferri (INAF-OAB) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 15:50:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located emission from the source 4U 1630-47 (== X Nor X-1) (trigger=521085). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 248.519, -47.411 which is RA(J2000) = 16h 34m 05s Dec(J2000) = -47d 24' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for long image triggers, there is no obvious variation in immediately available BAT lightcurve. The XRT began observing the field at 15:57:07.4 UT, 395.6 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 248.5063, -47.3934 which is equivalent to: RA(J2000) = +16h 34m 1.51s Dec(J2000) = -47d 23' 36.2" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This position is 1.8 arcseconds from that of a known X-ray source: 4U 1630-47. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 150 seconds with the White filter starting 405 seconds after the BAT trigger. No credible transient has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This source has been active recently (Bodaghee et al. ATel #3945). In the original GCN notice, the source was misidentified as IGR J16328-4726 . //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13280 SUBJECT: Fermi/GBM detection of a burst from the magnetar 1E 2259+5 DATE: 12/05/04 17:51:15 GMT FROM: Chryssa Kouveliotou at MSFC S. Foley (UCD), C. Kouveliotou (NASA/MSFC), Y. Kaneko (Sabanci University) and Andrew Collazzi (NASA/ORAU) report on behalf of the Fermi/GBM Team:   At 08:17:43.71 UT on 21 April 2012, the Fermi Gamma-Ray Burst Monitor triggered on a short, soft event very similar to an SGR burst (trigger 356689065/120421346).   The on-ground calculated location is RA = 357.0, DEC = 40.0(J2000 degrees, equivalent to 23h 48 m, 40d 00'), with an uncertainty of 12 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location is consistent with 1E 2259+586, albeit with a large error radius.   The event had a duration of ~ 40 ms (20-100 keV) and was equally well fit either with an OTTB function of kT=85+-17 keV or with a single blackbody spectrum of kT=17+-1 keV. These results are preliminary.   Untriggered event searches between April 18-24, 2012 (+- 3 days around the trigger time) did not reveal any additional bursts at the same significance level from the same direction.   Given the recent report by Archibald et al. (ATel 4080, 2012) about the detection of a flux increase of 1E 2259+586 with Swift, we suggest that this magnetar source was indeed the origin of the GBM burst.   Further observations of the source in multiple wavelengths are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13286 SUBJECT: Fermi Trigger 358364818: BOOTES-4 observations DATE: 12/05/11 21:38:11 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia S. Guziy (Mykolaiv Nat. Univ.), P. Kubanek (IP AS CR), Yufeng Fan (Yunnan Nat. Astr. Obs.) and A. J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report: "Following the possible detection (Gorbovskoy et al. GCN 13285) of an optical transient (10th mag) within the Fermi Trigger 358364818 error box, we have observed the field with the 0.6m BOOTES-4/MET robotic telescope at the Lijiang Astronomical Observatory, China. r'-band images (120 s each) were obtained starting at 19:26 UT on May 11. No source is detected at the reported MASTER-II position down to a 19.5 limiting magnitude" This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13287 SUBJECT: Fermi GBM Trigger 358364818 is not a GRB DATE: 12/05/11 23:42:20 GMT FROM: Valerie Connaughton at UAH/NSSTC Valerie Connaughton (UAH) and David Byrne (UCD) report on behalf of the Fermi GBM Team: "The event which triggered the Fermi Gamma-ray Burst Monitor at 17:46:57 UT on 10 May 2012 (120510741/358364818) is not a GRB. This event was classified as being of uncertain origin by the GBM Flight Software owing to an inability to localize it on-board. Inspection of the data suggests that this event is of solar origin, correlating in time with a C-class solar flare seen in the GOES data. On-ground localization using the GBM data places the event within 2 deg of the Sun. The OT reported by Gorbovskoy et al. (GCN 13285) is thus not related to Fermi GBM trigger 358364818." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13299 SUBJECT: Swift Trigger 522245 is a noise fluctuation near IGR J17091-3624 DATE: 12/05/14 17:23:43 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), D. N. Burrows (PSU), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), B. Gendre (ASDC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/PSU), M. C. Stroh (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: As part of a campaign to detect faint nearby GRBs, BAT has lowered its threshold to events near to known sources and nearby Galaxies. At 16:53:59 UT, the Swift Burst Alert Telescope (BAT) triggered at this lower threshold in the vicinity of the known source IGR J17091-3624. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 257.313, -36.282 which is RA(J2000) = 17h 09m 15s Dec(J2000) = -36d 16' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers, the immediately available lightcurve show no obvious variation. The XRT began observing the field at 16:56:02.5 UT, 122.7 seconds after the BAT trigger. No source was detected in central 8x8 arcminute window in 641 s of promptly downlinked data. IGR J17091-3624 is outside of this promptly downlinked window. UVOT took a finding chart exposure of 150 seconds with the White filter starting 127 seconds after the BAT trigger. No credible new source has been found in the initial data products. The 8'x8' region for the list of sources generated on board covers 100% of the BAT error circle, but not the IGR J17091-3624 source. The list of sources is typically complete to about 18 mag. Given the marginal significance of the BAT detection (5.84 sigma) the distance of the BAT detection from the known source location (7.5 arcmin) and the lack of detection by the narrow field instruments, we believe that this is not a true detection of an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13314 SUBJECT: Swift starts a new program to find fainter transients DATE: 12/05/21 15:55:01 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), D.M. Palmer (LANL) and Neil Gehrels (GSFC) for the Swift Team: PUNCHLINE: Swift has started a new campaign structured to detect fainter transients in nearby galaxies -- in particular subluminous long GRBs and SGR Superflares. (This campaign started ~13:00 UT 14 may 2012.) INTRO: Swift/BAT lowered the triggering threshold for peaks in the image domain that are near locations of known sources in the on-board catalog. It is called the "interesting source" threshold. We are lowering it from 6.40 sigma (where it has been for years) to 5.80 sigma. To satisfy the interesting source threshold, a peak in the image domain must be greater than 5.80 sigma AND it must be within a 12 arcmin radius of one of these sources in the catalog AND the peak intensity minus the current on-board threshold intensity for that source must be greater than 2 sigma. We have about 600 nearby galaxies (distance < 20 Mpc) in the on-board catalog, ~70 tiles covering M31, and ~600 other known hard x-ray sources. For the 670 galaxy entries (nearby and M31), their thresholds have been set to 0. For nearly all of the 600 known sources, their thresholds are twice their previous trigger level. It is the "(peak_intensity - threshold_intensity) > 2 sigma" that inhibits this new Interesting Source trigger from firing on the many known sources. We are going after the underluminous long GRBs and SGRs in the nearby galaxies. DETAILS: The following bullets describe key aspects about the information you will receive for these Interesting Source triggers: * The full, normal set of Swift GCN Notices will be produced for these triggers. And these Notices will have their full set of information content; there is no format or content change for these triggers. These triggers (in the 5.8 - 6.4 sigma range) will still cause BAT to trigger and produce the normal set of messages down TDRSS, through GCN, and out to the world, ie BAT_POS, BAT_LC, BAT_SCALEDMAP, FOM, SC_SLEW, XRT_POS_[NACK], etc. * If the spacecraft decides it is safe to slew (just like normal), then the spacecraft will slew and the XRT & UVOT will produce their normal set of observations and GCN notices (including updates). (On rare occaisions, the merit value of the new interesting source will be below the merit value of the target currently being observed, and so no slew will occur until a planned target of lower merit value comes along AND the interesting source is still visible.) * Since, by definition, these triggers will be spatially coincident with a source in the on-board BAT catalog, there will be a COMMENT line in the full-format GCN email notice that says "this matches source XYZ123 in the on-board catalog; delta=0.NNN [deg]". And a COMMENT line "this matches source XYZ123 in the ground catalog; delta=0.NNN [deg]". Because the matching tolerance (12 arcmin=0.20 deg) is much larger than the typical BAT position error (3 arcmin=0.05 deg), most spurious events will have a delta > 0.07 deg. However, a large delta can also indicate a true object in the halo of a galaxy (35 kpc @ 10 Mpc = 0.2 deg). * Because of these catalog matches, GCN will label the trigger as a TRANSIENT (not a GRB). (So there will be the usual two GCN notices go out for these catalog-matching triggers: (a) the BAT_GRB_POS notice, and (b) the BAT_TRANSIENT notice. * Other noteworthy pieces of information for these Interesting Sources are: (a) these Interesting Source triggers can result from both Rate Triggers (4msec - 32 sec) and from Image Triggers (Trigger_Dur > 60 sec). (b) the "IMAGE_SIGNIF: 5.83 [sigma]" line in the BAT_POS notice will have a value between 5.8 & 6.4. This will also cause a COMMENT line to appear to the effect of "low image significance...". (c) If the "TRIGGER_DUR: 0.032 [sec]" has a small value (probably 4 to ~128 msec), then it is likely an SGR Superflare or a Short GRB in nearby galaxy or noise. If it is a big value, then it is either a long GRB or a hard x-ray transient in a nearby galaxy, or noise. OCCURANCE RATE: We currently estimate that the false positive rate will be ~1 per week. If this turns out to be significantly off, we will adjust the 5.80 value higher or lower accordingly. The rate of reals is somewhat harder to calculate, but is expected to be in the 0.5-1 per month range. RAPID-RESPONSE CIRCULARS: The Swift Team will issue its rapid-response Circular only if the trigger is a real astrophysical source, but not for noise-caused triggers (this is because the Team is getting smaller and this would increase the work-load). These rapid-response Circulars are typically issued within 30 min of the trigger time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13347 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 120527.573 is not a GRB DATE: 12/05/29 15:33:41 GMT FROM: Arne Rau at MPE Arne Rau reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 120527.573 at 13:45:14.73 UT on 27 May 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger has been caused by particle events." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13352 SUBJECT: Fermi GBM trigger 120602.539 is not a GRB DATE: 12/06/02 18:31:51 GMT FROM: David Gruber at MPE David Gruber (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 360334602 (120602539) at 12:56:40.41 UT on 02 June 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13355 SUBJECT: GBM triggers 120604.526 & 120604.399 were not GRBs DATE: 12/06/05 15:11:23 GMT FROM: Arne Rau at MPE Arne Rau (MPE Garching) reports on behalf of the Fermi/GBM team: The GBM triggers 120604.399 and 120604.526, both originally classified as GRBs, have in fact been caused by a solar flare and local particles, respectively. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13367 SUBJECT: Swift triggers (#524542) on a Galactic source DATE: 12/06/17 16:12:08 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), V. D'Elia (ASDC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and G. Stratta (ASDC) report on behalf of the Swift Team: At 15:46:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located a likely Galactic source (trigger=524542). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 282.785, +0.025 which is RA(J2000) = 18h 51m 08s Dec(J2000) = +00d 01' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger (64 sec), the lightcurve does not show anything significant. The XRT began observing the field at 15:49:47.3 UT, 171.7 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 282.8107, -0.0010 which is equivalent to: RA(J2000) = 18h 51m 14.57s Dec(J2000) = -00d 00' 03.6" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 131 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.0 arcseconds from that of a known X-ray source: 2XMM J185114.3-000004 in the XMM-NEWTON XMMSSC catalogue. The catalogued count-rate of this source is equivalent to approximately 0.013 XRT count/sec; the mean count-rate in the promptly-available XRT data is 0.56 count/sec. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 175 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain extinction expected. Due to the extended duration of this detection and the proximity to the Galactic plane (0.04 degrees), we believe that this is most likely the Galactic source 2XMM J185114.3-000004 . However this is a crowded field and we cannot rule out the possibility that this is a different Galactic source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13368 SUBJECT: Trigger 524584: Swift detection of Algol DATE: 12/06/18 12:00:18 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), S. R. Oates (UCL-MSSL), G. Stratta (ASDC) and V. N. Yershov (UCL-MSSL) report on behalf of the Swift Team: At 11:33:11 UT, the Swift Burst Alert Telescope (BAT) triggered on the flare star Algol (trigger=524584). Swift did not slew because of the Sun observing constraint. The BAT on-board calculated location is RA, Dec 47.017, +40.966, which is RA(J2000) = 03h 08m 04s Dec(J2000) = +40d 57' 57" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (7 min), the TDRSS lightcurve does not show anything significant. This trigger was in the new category of subthreshold matchup with known sources in the on-board catalog (imager signif=5.83 sgima). However, the BAT position is 1.2 arcmin from Algol, so the chance coincidence proability is low, but we can not rule that out. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13369 SUBJECT: Swift Trigger 524642 is Swift J1910.2-0546 DATE: 12/06/18 19:52:20 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), S. T. Holland (STScI), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU), E. Sonbas (NASA/GSFC/Adiyaman Univ.) and G. Stratta (ASDC) report on behalf of the Swift Team: At 19:06:47 UT, the Swift Burst Alert Telescope (BAT) triggered on Swift J1910.2-0546 (trigger=524642). Swift will execute a delayed slewed due to the Earth observing constraint (49 min delay). The BAT on-board calculated location is RA, Dec 287.577, -5.806, which is RA(J2000) = 19h 10m 18s Dec(J2000) = -05d 48' 22" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (27 min), the TDRSS lightcurve does not show anything significant. Due to an observing constraint, Swift will not slew until 20:30UT. There will be no XRT or UVOT data until this time. Swift J1910.2-0546, discovered by BAT on May 30th, 2012 (Krimm et al., ATEL #4139), has been seen to be rising in the BAT Transient Monitor for several days, leading to this trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13373 SUBJECT: Swift trigger 524642 / SwJ1910.2-0546 DATE: 12/06/21 14:39:45 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev, K. Antonyuk (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift trigger 524642 with AZT-11 telescope of CrAO observatory starting on June 18 (UT) 20:23:03 under favorable weather conditions and seeing of about 2.4 arsces. At the edge of the Swift-XRT localization (+19h 10m 22.39s -05d 47' 55.3" GRB_ERROR=5.2") we found bright optical source which is absent on any DSS2 plates. The coordinates of the source (J2000) 19 10 22.78 -05 47 56.4 is 5.9" away from the center of the XRT localization and coincide with UVOT position reported in GCN/SWIFT NOTICE. Photometry of the source is based on the USNO-B1.0 star 0842-0520198 (19 10 23.32 -05 46 52.8) assuming R=14.70: T0+ Filter, Exposure, OT, uplim (3 sigma) (mid, d) (s) 0.0666 R 13x180 16.033 +/- 0.005 21.7 The finding chart can be found at http://grb.rssi.ru/Swift_524642/Swift_524642_20120618_R_AZT11.PNG //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13375 SUBJECT: Swift Trigger 524949: Noise fluctuation near a galaxy DATE: 12/06/23 06:48:53 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 06:08:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible near-threshold image peak near the location of the nearby galaxies NGC4405 and NGC 4383 (trigger=524949). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 186.424, +16.302, which is RA(J2000) = 12h 25m 42s Dec(J2000) = +16d 18' 09" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As it typical with image trigger (11.7 min) the TDRSS lightcurve does not show anything significant. The XRT began observing the field at 06:25:33.5 UT, 1029.9 seconds after the BAT trigger. No source was detected in 631 s of promptly downlinked data, which covered 82% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart if any. UVOT took a finding chart exposure of 150 seconds with the White filter starting 1033 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. As part of a sensitivity enhancement program for Swift, we now do follow-up observations on weak fluctuations near to a catalog of ~600 nearby galaxies and other objects. Most of these follow-ups are expected to be noise fluctuations. Given the lack of an XRT confirmation it is most likely that this source one of those false triggers. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13386 SUBJECT: Swift detection of IGR J17062-6143 DATE: 12/06/25 23:03:17 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. A. Kennea (PSU), A. Melandri (INAF-OAB), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 22:42:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located IGR J17062-6143 (trigger=525148). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 256.609, -61.728 which is RA(J2000) = 17h 06m 26s Dec(J2000) = -61d 43' 40" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers (duration = 64 sec), the real-time lightcurve does not show anything significant. The XRT began observing the field at 22:45:05.2 UT, 153.6 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 256.5681, -61.7098 which is equivalent to: RA(J2000) = +17h 06m 16.34s Dec(J2000) = -61d 42' 35.3" with an uncertainty of 5.7 arcseconds (radius, 90% containment). This location is 95 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 0.1 s image was 2.25e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 321 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 17:06:16.27 = 256.56779 DEC(J2000) = -61:42:40.0 = -61.71112 with a 90%-confidence error radius of about 0.61 arc sec. This position is 4.8 arc sec. from the center of the XRT error circle. The estimated magnitude is 15.84 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.15. IGR J17062-6143 is a known X-ray transient with a location of RA=256.56771, DEC=-61.71125 (RA=17 06 16.3, DEC=-61 42 40.5) with an uncertainty of 0.3 arc sec (ATEL #1840; Ricci et al.), consistent with this detection. The nature of this transient is unknown and further observation are warranted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13388 SUBJECT: Swift detection of Ginga 0834-430 DATE: 12/06/26 00:04:31 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), P. D'Avanzo (INAF-OAB), S. T. Holland (STScI), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 23:22:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located Ginga 0834-430 (trigger=525152). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 128.970, -43.187 which is RA(J2000) = 08h 35m 53s Dec(J2000) = -43d 11' 14" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As it typical with image triggers (duration = 22 min), the real-time TDRSS lightcurve does not show anything significant. The XRT began observing the field at 23:50:09.3 UT, 1673.8 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 128.97885, -43.18552 which is equivalent to: RA(J2000) = 08h 35m 54.92s Dec(J2000) = -43d 11' 07.9" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 23 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. This position is 2 arcseconds from that of a known X-ray source: Ginga 0834-430 in the Simbad catalogue. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.01 x 10^22 cm^-2, Kalberla et al. 2005), with an excess column of 2.2 (+2.63/-1.66) x 10^22 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 1674 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13390 SUBJECT: Skynet/PROMPT observations of IGR J17062-6143 (Swift trigger 525148) DATE: 12/06/26 02:31:22 GMT FROM: Kevin Ivarsen at UNC/PROMPT K. Ivarsen, J. Haislip, A. LaCluyze, D. Reichart, J. Moore, H. T. Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E. Speckhard, A.Trotter, and J. A. Crain report: Skynet observed the field of IGR J17062-6143 using the PROMPT telescopes located at CTIO in Chile following Swift trigger 525148 (Barthelmy et al.) and beginning 16.9 minutes after the trigger. Earlier observations were delayed due to evening twilight. We detect a fading optical afterglow at RA=17:06:16.3, Dec=-61:42:40.3 with the following preliminary magnitudes: mean-t  #exp  explen  filt  mag  +(1sig) -(1sig) 19.02m    1     80s    B   18.38  0.14    0.12 32.75m    4     80s    B   18.98  0.14    0.12 49.55m   17     80s    B   19.45  0.10    0.09 116.18m  58     80s    B   19.96  0.09    0.08 32.00m    4     80s    V   18.84  0.13    0.11 48.48m   17     80s    V   19.52  0.12    0.11 117.22m  60     80s    V   19.93  0.10    0.09 17.55m    1     80s    R   18.28  0.15    0.13 32.82m    4     80s    R   18.90  0.13    0.11 47.88m   17     80s    R   19.19  0.08    0.08 116.18m  56     80s    R   19.69  0.08    0.07 32.35m    5     80s    I   19.63  0.30    0.24 47.88m   14     80s    I   19.64  0.17    0.15 117.55m  58     80S    I   20.33  0.14    0.12 Magnitudes were calibrated to five stars in the USNO-B1.0 catalog. Further BVRI observations are planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13392 SUBJECT: XRF 120626B: MAXI/GSC detection DATE: 12/06/28 09:12:17 GMT FROM: Motoko Suzuki at RIKEN Y. Nakano (AGU), H. Negoro (Nihon U.), M. Serino, T. Mihara, M. Sugizaki,T. Yamamoto, J. Sugimoto, M. Matsuoka (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Ishikawa (JAXA), N. Kawai, M. Morii, R. Usui, K. Ishikawa (Tokyo Tech), A. Yoshida (AGU), H. Tsunemi, M. Kimura (Osaka U.), M. Nakajima, M. Asada, H. Sakakibara, N. Serita (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu, R. Sato (Kyoto U.), Y. Tsuboi, M. Higa (Chuo U.) M. Yamauchi, Y. Nishimura, T. Hanayama, K. Yoshidome (Miyazaki U.), K. Yamaoka (Waseda U.) report on behalf of the MAXI team: At the scan transit centered at UT 2012-06-26T13:38:14 (UT), MAXI/GSC detected a short X-ray transient lasted at least for 27 seconds within the 45 seconds triangular transit response of MAXI/GSC. Judging from its high galactic latitude (+47deg) and spectral hardness ratio, this transient is probably an X-ray flash. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (175.77deg,+68.50deg) = (11 43 04, +68 30 00)(J2000) which has a statistical uncertainty of 30 arcmin at the 90% confidence limit and an additional systematic uncertainty of 6 arcmin (90% containment radius). The burst was bright in 2-4 keV band. The flux of the source was 80 +- 20 mCrab (2-4 keV). There was no significant detection at the transit location in the previous and the following orbits (92 min before and after the detection) with an upper limit of 20 mCrab. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13396 SUBJECT: Watcher follow-up observations of IGR J17062-6143 (Swift trigger 525148) DATE: 12/06/28 11:33:33 GMT FROM: Seamus Meehan at U College,Dublin S. Meehan, L. Hanlon, M. Topinka (UCD Dublin), P. Kubanek (FZU AV CR Prague), report on behalf of a large collaboration: We imaged the field of IGR J17062-6143 detected by Swift (trigger 525148) with the Watcher robotic telescope (D=40cm) located at Boyden Observatory, Bloemfontein, South Africa. The first on-target observation started 300 seconds after the BAT trigger time of 22:42:31 UT and before the earliest PROMPT observations reported in GCN 13390. The initial airmass was 1.2 and conditions were non-photometric. The initial two exposures were taken in the Clear filter and were 30 seconds long. We detect a source at the position of the UVOT source (GCN 13386) in the first image with R-band magnitude of 14.8 ± 0.3 (4-sigma) with the limiting magnitude in the frame being 15.6 mag (2-sigma upper limit). In the second image the source is not detected, but the limiting magnitude is 15.1. These results are not sufficient to confirm fading behavior as seen at later times by PROMPT (GCN 13390) and GROND (ATEL 4214). Later images obtained by Watcher are being analysed. Magnitudes were estimated using the nearby USNO-B1 stars as references and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13399 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 120628.973 is not a GRB DATE: 12/06/29 01:15:17 GMT FROM: Michael Burgess at UAH Subject: Fermi Gamma-ray Burst Monitor trigger 120628.973 is not a GRB J. Michael Burgess (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: The Fermi Gamma-ray Burst Monitor (GBM) trigger 120628.973 at 23:20:41 UT on 28 June 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a particle event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13407 SUBJECT: Swift Trigger 525554 is noise DATE: 12/07/03 16:06:43 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC) and P. Evans (U Leicester) for the Swift team: Using the BAT data set from T-60 to T+243 sec from recent telemetry downlinks, we confirm that Swift-BAT trigger 525554 (Gehrels, et al., GCN Circ. 13401) is due to noise and is not anything astrophysical. We have 9ks of XRT data, starting at T+130s and going out to T+19ks. There are no sources in the BAT error circle, with a 3-sigma upper limit of 8e-4 ct/sec. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13419 SUBJECT: GBM triggers 120705.153 & 120705.322 were not GRBs DATE: 12/07/05 14:04:19 GMT FROM: Arne Rau at MPE Arne Rau (MPE Garching) reports on behalf of the Fermi/GBM team: The GBM triggers 120705.153 and 120705.322, both originally classified as GRBs, have in fact been caused by solar activity. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13475 SUBJECT: Trigger 526660: Swift detection of 1 E 1841-045 (aka Kes 73) DATE: 12/07/15 04:56:24 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), S. R. Oates (UCL-MSSL) and T. Sakamoto (NASA/UMBC) report on behalf of the Swift Team: At 04:31:08 UT, the Swift Burst Alert Telescope (BAT) triggered on an outburst 1E 1841-045 (aka Kes 73) (trigger=526660). Swift did not slew because it was given a low merit value (as is typical for known-source triggers). The BAT on-board calculated location is RA, Dec 280.349, -4.958, which is RA(J2000) = 18h 41m 24s Dec(J2000) = -04d 57' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration less than 64 msec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~0 sec after the trigger. We note that BAT previously triggered on this source on 02 July 2011. There is a known SGR at this location. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13480 SUBJECT: Swift-BAT refined analysis of 1E 1841-045 (Trigger=526660) DATE: 12/07/15 13:46:50 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC) (on behalf of the Swift-BAT team): Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report further analysis of 1E 1841-045 (aka Kes 73) (trigger #526660) (Barthelmy, et al., GCN Circ. 13475). The BAT ground-calculated position is RA, Dec = 280.374, -4.923 deg which is RA(J2000) = 18h 41m 29.8s Dec(J2000) = -04d 55' 23.4" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 44%. The mask-weighted light curve shows a singple spike (possibly 2 overlapping spikes) starting at ~T-0.008 and ending at ~T+0.012 sec. T90 (15-350 keV) is 0.012 +- 0.006 sec (estimated error including systematics). The time-averaged spectrum from T-0.008 to T+0.012 sec fit by a simple power-law model shows the power law index of 2.66 +- 0.40 (chi squared 50.1 for 57 d.o.f.). The fluence in the 15-150 keV band is 1.2 +- 0.3 x 10^-8 erg/cm2. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 8.77 +- 1.67 keV (chi squared 40.8 for 59 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/526660/BA/ We note the previous activity of this source: Swift BAT triggers 456505 on 02 Jul 2011 (GCN 12103 & 12104), 455904 on 23 Jun 2011 (GCN 12079 & 12082), and 445776 on 11 Feb 2011 (GCN 11673). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13486 SUBJECT: Fermi GBM trigger 120716.498 is not a GRB DATE: 12/07/17 15:37:01 GMT FROM: Sinead McGlynn at Excellence Cluster/TUM S. McGlynn (TUM/MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 364132647 (120716498) at 11:57:24.68 UT on 16 July 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13502 SUBJECT: Correction for GCN circ. 13500 DATE: 12/07/22 16:44:36 GMT FROM: L.P. Xin at NAOC L. P. Xin, J. Y. Wei, Y. L. Qiu, J. Wang, J. S. Deng, C. Wu, X. H. Han on behalf of EAFON report: We apologize for the wrong result reportd in GCN circ. 13500 . Caused by a wrong astronomical calibration, the optical candidate reported in GCN circ. 13500 should be a known object in the USNO B1.0 Therefore, no any new source within the location of XRT counterpart was detected by TNT. The 3 sigma upper limit of 19 mag was derived relatively to USNO B1.0 R2 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13522 SUBJECT: Swift Trigger 528925 is probably a noise fluctuation DATE: 12/07/27 22:38:37 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), V. Mangano (INAF-IASFPA), A. Maselli (INAF-IASFPA) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 22:24:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible source (trigger=528925). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 186.547, +18.066 which is RA(J2000) = 12h 26m 11s Dec(J2000) = +18d 03' 59" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for 1-min image triggers, the real-time TDRSS lightcurve does not show anything significant. This trigger has an image significance of 5.86 sigma, therefore this is an Interesting-Source subthreshold trigger. The XRT began observing the field at 22:27:12.8 UT, 146.3 seconds after the BAT trigger. No source was detected in 353 s of promptly downlinked data, which covered 90% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 151 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Due to the low significance of the BAT image (5.86 sigma), the large offset from the nominal catalog match (0.161 degrees from NGC4394) and the non-detection any source with XRT, we believe that this is a statistical fluctuation, rather than any astrophysical source. As part of a campaign to increase sensitivity to nearby GRBs, we have lowered the threshold for positions in the vicinity of nearby galaxies such as NGC4394, which also increases the false-positive rate. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13527 SUBJECT: Trigger 529076: Swift possible detection of SwJ1910.2-0546 DATE: 12/07/29 08:21:55 GMT FROM: Tilan Ukwatta at MSU M. M. Chester (PSU), V. Mangano (INAF-IASFPA), A. Maselli (INAF-IASFPA) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 07:13:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source (trigger=529076). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 287.652, -5.699 which is RA(J2000) = 19h 10m 37s Dec(J2000) = -05d 41' 54" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peak structure with a duration of about 20 sec. The peak count rate was ~1464 counts/sec (15-350 keV), at ~11 sec after the trigger. The XRT began observing the field at 07:16:01.7 UT, 139.3 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 287.5950, -5.8003 which is equivalent to: RA(J2000) = +19h 10m 22.80s Dec(J2000) = -05d 48' 01.1" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 417 arcseconds from the BAT onboard position and 66 arcseconds from the known source SwJ1910.2-0546. As this position is significantly outside the BAT error circle, it is probably unrelated to the trigger. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 6.25e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 306 seconds after the BAT trigger. There is a counterpart to the XRT source in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 19:10:22.80 = 287.59499 DEC(J2000) = -05:47:55.8 = -5.79884 with a 90%-confidence error radius of about 0.62 arc sec. This position is 4.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 16.17 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.61. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13538 SUBJECT: Swift Trigger 529076 is from Swift J1910.2-0546 and is not a GRB DATE: 12/07/29 18:16:45 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA) for the Swift team Further analysis of the Swift/BAT event data from Trigger 529076 (GCN Circ 13530, Ukwatta et al) yields a significance of 5.4-sigma. Over the time range we have data (T-120 to T+180 sec), the mask-weighted light curve shows constant emission with no significant features on time scales typical of a gamma-ray burst. Therefore we conclude that this trigger was not due to a GRB. The XRT and UVOT positions reported in GCN Circ 13530 are consistent within reported errors of the position for Swift J1910.2-0546 (ATel #4144; Rau, Greiner, and Schady). Also this source has been steadily brightening in the BAT hard X-ray transient monitor (average of 0.021 ± 0.001 ct/s/cm^2 (~100 mCrab) in the 15-50 keV band for 28-July-2012). Therefore we conclude that Trigger 529076 was caused by Swift J1910.2-0546, but that low statistics in the trigger interval yielded a BAT position inconsistent with this known source. -- Dr. Hans A. Krimm Universities Space Research Association CRESST and NASA Goddard Space Flight Center Code 661, ASD Greenbelt, MD 20771 USA 301-286-6955 fax 301-286-0677 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13540 SUBJECT: Correction to Swift GCN Circular 13538 DATE: 12/07/29 19:17:26 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA) for the Swift team The recent GCN Circular (GCN Circ 13538, Krimm) contained an error in referencing an earlier Circular. The reference should have been to GCN Circ 13527, Chester et al. All other information is correct and the conclusion that BAT trigger 529076 is from Swift J1910.2-0546 is correct. I apologize for this error and thank T. Ukwatta and E. Sonbas for pointing it out. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13596 SUBJECT: Swift-BAT trigger 529813 is due to noise while entering the SAA DATE: 12/08/06 17:25:25 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC) on behalf of the Swift-BAT team report: In the real-time GCN Notices, this was reported as a event from IGR J16207-5129 (with a large angular separation (10 arcmin) and low image_domain significance (5.88 sigma)). Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report ground analysis of BAT trigger #529813. The image significance has dropped to 3 sigma. This trigger was caused by noise while entering the SAA and had a chance spatial coincidence with the IGR source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13597 SUBJECT: Swift trigger 530214: uncertain if real or not DATE: 12/08/06 18:02:41 GMT FROM: Scott Barthelmy at NASA/GSFC F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), K. L. Page (U Leicester), M. H. Siegel (PSU), E. Troja (NASA/GSFC/ORAU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 17:33:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 530214. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 55.318, +40.930 which is RA(J2000) = 03h 41m 16s Dec(J2000) = +40d 55' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single pulse with a duration of about 10 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 17:35:06.4 UT, 94.5 seconds after the BAT trigger. No source was detected in 1.2 ks of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 98 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.25. Given the non-detection by XRT and UVOT, and the somewhat low significance in the BAT image plane, and a somewhat odd shape to the BAT lightcurve, it is likely that this is not a real astrophysical transient, but we can not rule it out. Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13599 SUBJECT: Swift-BAT trigger 530214 is noise DATE: 12/08/06 20:28:20 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC) and F. E. Marshall (NASA/GSFC) on behalf of the Swift-BAT team report: The Swift-BAT trigger (530214) at 17:33:31 UT (Circ 13597) is not a GRB or anything astrophysical. It was due to a noisy detector. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13600 SUBJECT: Fermi/GBM detection of an SGR-like burst DATE: 12/08/06 20:41:00 GMT FROM: Chryssa Kouveliotou at MSFC S. Foley (UCD/MPE), C. Kouveliotou, A.C. Collazzi (NASA/MSFC), Y. Kaneko (Sabanci University), D. Palmer (LANL) report on behalf of the Fermi/GBM and Swift/BAT Teams: "At 12:22:21.26 UT on 28 July 2012, the Fermi Gamma-Ray Burst Monitor triggered on an SGR-like event (trigger 365170944/120728516). The on-ground calculated location, using the GBM trigger data, is RA = 282.2, DEC = -0.8 (J2000 degrees, equivalent to 18 h 49 m, -00 d 49'), with an uncertainty of 1.7 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 45 degrees. The GBM light curve consists of a single pulse with a duration (T90) of 48 +/- 6ms (10-300 keV). The time-averaged spectrum from T0-0.020 s to T0+0.048 s is equally well fit by a power law function with an exponential high-energy cutoff or by two blackbody functions. The power law index is -0.4 +/- 0.3 and the cutoff energy, parameterized as Epeak, is 32.6 +/- 1.7 keV. The low(high) energy blackbody temperatures are kT=4.4+/-0.6 and 12.1+/-0.9 keV, respectively. The event fluence (10-1000 keV) in this time interval is (4.0 +/- 0.2)E-7 erg/cm^2 (estimated using the power law with an exponential high-energy cutoff). The 64-ms peak photon flux measured starting from T0+0 s in the 8-1000 keV band is 103.4 +/- 3.0 ph/s/cm^2, or (4.4 +/- 0.1)E-6 erg/s/cm^2. An untriggered event search between July 25 - 31, 2012 did not reveal any additional burst from a direction of an SGR active region including SGR J1833-0832, AXP1841-045, PSRJ1846-0258, and AXP1845-0258. At this point we cannot confirm any of these sources as the origin of the burst as well as exclude the activation of a new SGR source. None of the above sources was visible by Swift during the GBM burst. Further, the Swift/BAT did not detect any other SGR-like events within 24 hours from the GBM trigger. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13612 SUBJECT: Swift Trigger 530441 is a false trigger DATE: 12/08/09 06:52:00 GMT FROM: David Palmer at LANL B. N. Barlow (PSU), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), D. M. Palmer (LANL) and P. Romano (INAF-IASFPA) report on behalf of the Swift Team: At 06:14:54 UT, the Swift Burst Alert Telescope (BAT) found a marginal-significance peak in the vicinity of IGR J16283-4838 (trigger=530441). Swift did not immediately slew to the burst due to the low priority the onboard software gives to this source. The BAT on-board calculated location is RA, Dec 246.932, -48.541 which is RA(J2000) = 16h 27m 44s Dec(J2000) = -48d 32' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, there is no obvious signal in the light curve. This image peak is almost certainly a noise fluctuation in an image. As part of an ongoing sensitivity enhancement program, we generate a GCN notice whenever a marginal significance peak is found within 12 arcminutes of a source in the on-board catalog. Given the low significance (6.43 sigma) and inconsistent position (0.126 degrees from the catalogued position), there is no reason to believe that this peak is due to the astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13619 SUBJECT: Trigger 530588: Swift detection of XMM J174457-2850.3 DATE: 12/08/11 05:10:08 GMT FROM: Scott Barthelmy at NASA/GSFC B. N. Barlow (PSU), S. D. Barthelmy (GSFC), C. Gronwall (PSU), D. M. Palmer (LANL) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 04:43:53 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Galactic center region (trigger=530588). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 266.257, -28.852 which is RA(J2000) = 17h 45m 02s Dec(J2000) = -28d 51' 08" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 20 sec. The peak count rate was ~1600 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 04:45:02.9 UT, 69.2 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 266.2395, -28.8389 which is equivalent to: RA(J2000) = +17h 44m 57.48s Dec(J2000) = -28d 50' 20.0" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 72 arcseconds from the BAT onboard position, within the BAT error circle. This position is 1.8 arcseconds from that of a known X-ray source: XMM J174457-2850.3, which is known to be currently active. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 4.33e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 234 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13703 SUBJECT: Fermi trigger 368003226 : MASTER optical observations DATE: 12/08/30 11:41:01 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs H. Levato and C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) C. Mallamaci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA) E. Gorbovskoy, V. Lipunov, V. Kornilov, D. Denisenko, A. Kuznetsov, D. Kuvshinov, A. Belinski, N. Tyurina, N. Shatskiy, P. Balanutsa, D. Zimnukhov, V.V. Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute A. Tlatov, A.V. Parhomenko, D. Dormidontov, V. Sennik Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, S. Yazev, N.M. Budnev, O. Gres, O. Chuvalaev, V.A. Poleshchuk Irkutsk State University V. Yurkov, Yu. Sergienko, D. Varda, E. Sinyakov Blagoveschensk Educational State University, Blagoveschensk V. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University MASTER-ICATE robotic very wide field cameras (FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec, http://observ.pereplet.ru) located in Argentina (Observatorio Astronomico Felix Aguilar, http://93.180.27.230:8080/) were pointed to the FERMI trigger 368003226 18 s after notice time and 44 s after GRB time at 2012-08-30 07:07:47 UT. We cover full 1-sigma and part of 3-sigma FERMI error-box (76.836d, -27.824d error 2.99) We haven`t found optical transient within FERMI error-box our first (5 s exposure) set and on coadd image made of 60 images and complete exposure of 300 seconds. The coverage map is available http://master.sai.msu.ru/static/GRB120830_covermap.jpeg The 5-sigma upper limit on single image has been about 11.0 mag and 12.0 mag on coadd image. Our cameras are continuously imaging the sky with 5 sec exposures. Weather conditions were not so good (feeble cloudiness). This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13774 SUBJECT: Swift Trigger 533836 is a new Galactic transient DATE: 12/09/16 10:05:16 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), D. Grupe (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift Team: At 09:16:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located an unidentified source near the Galactic center (trigger=533836). Swift slewed immediately to the source location. The BAT on-board calculated location is RA, Dec 266.322, -26.400 which is RA(J2000) = 17h 45m 17s Dec(J2000) = -26d 23' 58" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is a 16 minute long image trigger, so there is no immediately available lightcurve data. The on-board detection significance is 8.5 sigma. The XRT began observing the field at 09:36:59.0 UT, 1252.7 seconds after the BAT trigger. XRT found a possible X-ray source located at RA, Dec 266.2960, -26.4025 which is equivalent to: RA(J2000) = +17h 45m 11.04s Dec(J2000) = -26d 24' 09.0" with an uncertainty of 5.8 arcseconds (radius, 90% containment). This location is 84 arcseconds from the BAT onboard position, within the BAT error circle. We are waiting for the full dataset to download in order to confirm the existence of the source. The initial flux in the 2.5 s image was 8.01e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 1259 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain extinction expected. Due to its position 152 arcminutes from the Galactic center, and its duration (discovered in a 16-minute long imag trigger), we believe that this is a previously-uncatalogued Galactic transient. A final determination of the status of this source will require the downlinked data from the ground station. A 'Swift J' source name will be assigned based on the final X-ray position. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13775 SUBJECT: Swift Transient Swift J174510.8-262411: Swift-BAT refined analysis DATE: 12/09/16 22:39:03 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data sets from the recent telemetry downlinks, we report on the two BAT triggers on the new galactic source Swift J174510.8-262411 (BAT triggers 533836 and 533850) (Cummings, et al., GCN Circ. 13774). Trigger 533836: The partial coding was 48%. Using the data set from T-41 to T+557 sec (T=09:16:06.34), the mask-weighted light curve shows the source to be active when it came into the BAT FoV during a regular pre-planned slew. The flux was constant at 0.06 ph/cm2/sec. The time-averaged spectrum from T_0 to T+303 plus T+387 to T+557 sec (there is an 84-sec hole in the downlinked data at this time) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.78 +- 0.29. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/533836/BA/ Trigger 533850: The partial coding was 100%. Using the data set from T-239 to T+963 sec (T=12:36:22.34), the BAT ground-calculated position is RA, Dec = 266.335, -26.419 deg, which is RA(J2000) = 17h 45m 20.4s Dec(J2000) = -26d 25' 09.5" with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment). The mask-weighted light curve shows the source to be active when it came into the FoV at T-220 sec, and at a constant flux of 0.066 ph/cm2/sec out to T+950 sec. Plus the source has been continuously visible in the BAT onboard imaging data since the initial trigger in all observations (as of 14:50 UT). The time-averaged spectrum from T+0.0 to T+64.0 sec (the trigger integration interval) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.92 +- 0.41. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/533850/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13780 SUBJECT: Swift Trigger 534017 is probably not real. DATE: 12/09/18 12:25:19 GMT FROM: Caryl Gronwall at PSU/Swift-UVOT B. N. Barlow (PSU), W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), D. Grupe (PSU), E. A. Helder (PSU), J. A. Kennea (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 11:58:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger=534017. Swift slewed immediately to the trigger location. The BAT on-board calculated location is RA, Dec 345.700, -39.715 which is RA(J2000) = 23h 02m 48s Dec(J2000) = -39d 42' 52" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This event resulted from a 64s image trigger, and as usual for these events nothing is seen in the BAT light curve. This trigger was a sub threshold trigger (5.8 sigma significance), and is spatially coincident with a nearby galaxy (11 arc minutes from NGC 7456). Further analysis of data on the ground will be required to verify the reality of this event. The XRT began observing the field at 12:00:15.4 UT, 129.1 seconds after the BAT trigger. No source was detected in 157 s of promptly downlinked data, which covered 94% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 132 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13783 SUBJECT: Swift trigger 534017 was not an astrophysical vent DATE: 12/09/19 15:41:30 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU), W. H. Baumgartner (GSFC/UMBC), Dirk Grupe (PSU) and B. N. Barlow (PSU) report: We have analyzed the full XRT data set for Swift trigger 534017 (Barlow et al, GCN 13780). There are only 192s of XRT data available. We find no sources in the XRT field; the XRT data cover 100% of the BAT error circle. We thus conclude that trigger 534017 was not an astrophysical event. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13835 SUBJECT: Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA. DATE: 12/10/02 00:35:53 GMT FROM: Javier Gorosabel at IAA-CSIC J.C. Tello (IAA-CSIC), R. Gimeno (IAC), J. Gorosabel (IAA-CSIC), M. Jelinek (IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), report on behalf of a larger collaboration: "We observed the field of Swift trigger 535026 (D'Elia et al. GCN 13831) with the 82cm IAC80 telescope at the Observatorio del Teide, Tenerife, Spain. The observations were carried out in the I-band on 19:38--21:32 UT (starting 1.25 hours post burst) with a total exposure time of 18x240s. An optical source placed at RA(J2000)=18:24:07.88 DEC(J2000)=-05:39:55.0 (+/-0.9") shows a clear decay from I~19 to I~20 (Vega), against the USNO B1.0 catalogue. The coordinates of this source are consistent with the XRT error circle (GCN 13831) and the possible optical counterpart reported by Andreev et al. (GCN Circ. 13833). The object is also detected with the BOOTES-2/TELMA telescope at I~19.7 (Vega) at 20:49--21:52 UT Oct. 1." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13843 SUBJECT: Trigger 535733: Swift possible detection of SAX J1828.5-1037 DATE: 12/10/11 00:18:01 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 23:57:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 535733. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 277.193, -10.479 which is RA(J2000) = 18h 28m 46s Dec(J2000) = -10d 28' 42" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As typical for image triggers (64-sec), the prompt lightcurve data shows nothing significant. This position is marginally consistent with the known source SAX J1828.5-1037. We note that the detection significance is marginal as well. The XRT began observing the field at 23:59:42.7 UT, 120.5 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 6 seconds with the White filter starting 123 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. Results from the list of sources generated on-board are not available at this time. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13844 SUBJECT: Trigger 535747: Swift detection of an outburst from SGR1806-20 DATE: 12/10/11 03:13:02 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. T. Holland (STScI) and J. A. Kennea (PSU) report on behalf of the Swift Team: At 02:54:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from SGR 1806-20 (trigger=535747). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 272.130, -20.410 which is RA(J2000) = 18h 08m 31s Dec(J2000) = -20d 24' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 0.064 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0.0 sec after the trigger. The XRT began observing the field at 02:55:19.9 UT, 58.6 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 272.1635, -20.4112 which is equivalent to: RA(J2000) = 18h 08m 39.24s Dec(J2000) = -20d 24' 40.3" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 113 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.4 arcseconds from that of SGR 1806-20. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 63 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13851 SUBJECT: Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747) DATE: 12/10/11 20:59:24 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), S. T. Holland (STScI), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+807 sec from recent telemetry downlinks, we report further analysis of BAT trigger (#535747) from SGR1806-20 (Barthelmy, et al., GCN Circ. 13844). The BAT ground-calculated position is RA, Dec = 272.172, -20.448 deg, which is RA(J2000) = 18h 08m 41.2s Dec(J2000) = -20d 26' 52.3" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%. The mask-weighted light curve shows a single FRED-like pulse starting at ~T-0.05 sec, peaking at ~T+0.1 sec, with a long low-level tail out to T+0.5 or T+1.0 sec. T90 (15-350 keV) is 0.67 +- 0.16 sec (estimated error including systematics). There is no evidence of additional outbursts in the post 800 sec of the lightcurve at the 0.13 ph/cm2/sec upper limit. The time-averaged spectrum from T-0.05 to T+0.68 sec fit by a simple power-law model shows the power law index of 2.38 +- 0.42 (chi squared 69.8 for 57 d.o.f.). The fluence in the 15-150 keV band is 3.3 +- 0.8 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.18 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 8.1 +- 2.1 keV (chi squared 71.9 for 59 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 38.3 +- 21.6 keV (chi squared 68.1 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/535747/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13858 SUBJECT: Swift-BAT trigger 535733 is not astrophysical DATE: 12/10/12 00:51:53 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), C.B. Markwardt (GSFC), J.A. Kennea (PSU) on behalf of the Swift-BAT team report: Using the data set from T-239 to T+455 sec from recent telemetry downlinks, Swift-BAT trigger 535733 (GCN 13843) is not an astrophysical source. It is a chance noise fluctuation in the image domain near the location of SAX J1828.5-1037. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13866 SUBJECT: INTEGRAL Alert n.6678: NOT A GRB DATE: 12/10/13 21:44:21 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF-Milano), E.Bozzo (ISDC, Versoix) on behalf of the IBAS Localization Team report: The IBAS Alert Packet n. 6678 is not due to a GRB (the trigger was caused by an incorrect location of the Crab) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13885 SUBJECT: Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703 DATE: 12/10/22 18:46:47 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. J. Mountford (U Leicester), P. Romano (INAF-IASFPA) and M. C. Stroh (PSU) report on behalf of the Swift Team: At 18:08:06 UT, the Swift Burst Alert Telescope (BAT) triggered (536502) on a noise fluctuation in the image domain which we likely believe was a chance coincidence with the source SAX J1818.6-1703 in the on-board catalog. As is typical for image triggers (64 sec, image significance=5.81 sigma), the real-time TDRSS lightcurve does not show anything significant. The XRT began observing the field at 18:16:45.8 UT, 519.7 seconds after the BAT trigger. No source was detected in 441 s of promptly downlinked data, which covered 87% of the BAT error circle. We are waiting for the full dataset to detect and localise any possible XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 546 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13902 SUBJECT: Swift-BAT trigger 536502 is not astrophysical DATE: 12/10/26 00:07:42 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), J.A. Kennea (PSU), and P. Romano (INAF-IASFPA) on behalf of the Swift team report: Using the data set from T-73 to T+963 sec from recent telemetry downlinks, Swift-BAT trigger 536502 (GCN 13885) is not an astrophysical source. It is a chance noise fluctuation in the image domain near the location of SAX J1818.6-1703. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13905 SUBJECT: Swift Quick-look and HEASARC will be offline for 24 hours this weekend DATE: 12/10/26 16:55:50 GMT FROM: Scott Barthelmy at NASA/GSFC N. Gehrels, S. D. Barthelmy, F. E. Marshall (GSFC): This is a notification that the power for some of the computers at Goddard is going down for maintenance on Saturday and Sunday this weekend (starting at ~16:00 UT October 27, 2012, for a total of about 24 hours). The Swift quick look data at the Swift Data Center and archival data at the HEASARC will not be available. Archival data at the ASI Science Data Center and the UK Swift Science Centre will still be available. GCN Notice and Circular distribution will not be affected, but the GCN web pages will be offline. (There is some possibility that the hurricane may change these plans.) We apologize for the inconvenience. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13923 SUBJECT: Swift Quick-look and HEASARC will be offline for due to hurricane Sandy DATE: 12/10/29 12:20:17 GMT FROM: Scott Barthelmy at NASA/GSFC N. Gehrels, S. D. Barthelmy, F. E. Marshall (GSFC): This is a notification that some of the computers at Goddard are going to be pre-emptively taken down in preparation for the expected power outages due to hurricane Sandy (starting at ~13:00 UT October 29, 2012, for an unknown duration). The Swift Quick-look data at the Swift Data Center and archival data at the HEASARC will not be available. Archival data at the ASI Science Data Center and the UK Swift Science Centre will still be available. GCN Notice and Circular distribution will not be affected, but the GCN web pages will be offline. If, of course, there is an actual power outage, GCN Notice and Circular distribution will stop. We apologize for the inconvenience. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13933 SUBJECT: Swift Quick-look and HEASARC are back online DATE: 12/10/30 22:01:06 GMT FROM: Scott Barthelmy at NASA/GSFC N. Gehrels, S. D. Barthelmy, F. E. Marshall (GSFC): This is a notification that the Swift Quick-look data at the Swift Data Center and archival data at the HEASARC are back on line. They were offline for ~24 hours (Circ 13923). The storm has hurricane, and the computers have been re-powered and booted. There will be some lag in the processing and updating of the data sets and web pages as the backlog of telemetry data during the outage is processed. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13964 SUBJECT: Trigger 538084: Swift detection of XTE J1739-302 DATE: 12/11/11 09:52:24 GMT FROM: Hans Krimm at NASA-GSFC V. D'Elia (ASDC), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), A. Maselli (INAF-IASFPA), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 09:35:02 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from the SFXT source XTE J1739-302 (trigger=538084). The BAT on-board calculated location is RA, Dec 264.873, -30.360 which is RA(J2000) = 17h 39m 30s Dec(J2000) = -30d 21' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Since this was an image trigger, the light curve shows no significant features. The peak count rate was ~1000 counts/sec (15-350 keV), at ~2 sec after the trigger. The satellite did not slew to this source because the current observing target had a higher merit. Thus there will be no data for this source from the XRT or UVOT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13965 SUBJECT: Fermi GBM trigger 121115.186 is not a GRB DATE: 12/11/15 14:46:03 GMT FROM: David Tierney at UCD D. Tierney (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 374646503 (121115186) at 04:28:20.04 UT on 15 November 2012, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13966 SUBJECT: Swift trigger 538575: Magellan Observations DATE: 12/11/16 03:47:09 GMT FROM: Ryan Chornock at Harvard R. Chornock, E. Berger, W. Fong, D. Milisavljevic, and M. Drout (Harvard) report: We observed the error circle of Swift trigger number 538575 with IMACS on the Magellan/Baade 6.5-m telescope starting on 2012 November 16.137 UT (50 min after the trigger). In a single 180-sec r-band image we do not detect any new sources in comparison with the DSS to the depth of the survey image. Additional analysis is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13974 SUBJECT: Swift-BAT trigger 538575 is not astrophysical DATE: 12/11/18 22:38:44 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), P. Evans (U Leicester), J.Cummings (NASA/UMBC) on behalf of the Swift team report: Swift trigger 538575 was due to a noise fluctuation in the image domain near (8 arcmin) the catalog source NGC7462. This 8 arcmin distance, a low image significance (6.13 sigma), and the lack of an XRT source strongly indicates that this trigger is non-astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14098 SUBJECT: Trigger 543763: SGR 1E 1841-045: Swift detection of a soft gamma repeater burst (aka Kes 73) DATE: 12/12/23 23:06:28 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), S. T. Holland (STScI) and C. J. Mountford (U Leicester) report on behalf of the Swift Team: At 22:44:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1E 1841-045 / Kes 73 (trigger=543763). Swift did not slew because of the Sun observing constraint. The BAT on-board calculated location is RA, Dec 280.334, -4.902, which is RA(J2000) = 18h 41m 20s Dec(J2000) = -04d 54' 08" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The real-time lightcurve packets were corrupted so nothing is known about the shape of the light curve, but presumably it is a single spike (typical of this source); and the trigger duration was 16 msec. The source will remain in Sun constraint until Feb 13. There will be no further observations by Swift. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14099 SUBJECT: Swift-BAT refined analysis of SGR 1E 1841-045 (Trigger=543763) DATE: 12/12/24 19:38:58 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report further analysis of BAT trigger #543763 on SGR 1E 1841-045 (Barthelmy, et al., GCN Circ. 14098). The BAT ground-calculated position is RA, Dec = 280.303, -4.916 deg, which is RA(J2000) = 18h 41m 12.8s Dec(J2000) = -04d 54' 58.0" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a single spike where T90 (15-350 keV) is 0.012 +- 0.009 sec (estimated error including systematics). Several models are fit over the time-averaged spectrum from T+0.000 to T+0.016 sec. A simple power-law model yields a poor fit with the power law index of 2.60 +- 0.32 (chi squared 55.89 for 57 d.o.f.). The fluence in the 15-150 keV band is 1.2 +- 0.3 x 10^-8 erg/cm2. The cutoff power-law model yields a fit with E_peak = 40.6 +- 4.6 keV, power law indix = 3.6 +- 3.8, and chi squared 32.18 using 59 d.o.f. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 9.8 +- 1.0 keV (chi squared 34.05 for 59 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 34.36 +- 9.34 keV (chi squared 46.93 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/543763/BA/ We note the previous activity of this source: Swift BAT triggers 526660 15 Jul 2012 (GCN 13475 & 13480), 456505 on 02 Jul 2011 (GCN 12103 & 12104), 455904 on 23 Jun 2011 (GCN 12079 & 12082), and 445776 on 11 Feb 2011 (GCN 11673). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14119 SUBJECT: Swift Trigger 544381 is unlikely to be a GRB DATE: 12/12/29 13:26:04 GMT FROM: Mike Siegel at PSU/Swift MOC J. K. Cannizzo (NASA/UMBC), W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), T. Sakamoto (AGU), M. H. Siegel (PSU) and E. Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Swift Team: At 12:51:51 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger=544381, which is possibly, but unlikely to be, a GRB. Swift slewed immediately to the trigger location. The BAT on-board calculated location is RA, Dec 185.493, -47.928 which is RA(J2000) = 12h 21m 58s Dec(J2000) = -47d 55' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed weak structure superimposed on a rising count rate due to entry into the South Atlantic Anomaly. This, combined with the low image significance (6.8-sigma) makes this trigger unlikely to be a burst. However, further analysis of the full BAT data is required to make a final determination. The XRT began observing the field at 12:52:41.4 UT, 49.8 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the possible XRT counterpart. Full XRT and UVOT products are not available at this time because Swift entered the South Atlantic Anomaly shortly after the BAT trigger. Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14125 SUBJECT: Swift Trigger 544381 is a noise event DATE: 12/12/30 04:18:55 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA), J. K. Cannizzo (NASA/UMBC), Further analysis of the BAT event data for Swift trigger 544381 (Cannizzo et al, GCN 14119) shows that this event was a trigger on noise during a lead up to Swift's entry into the SAA. Therefore it is not a GRB or other astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14151 SUBJECT: Swift Trigger 547142: a probable Galactic source DATE: 13/01/28 06:51:28 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), H. A. Krimm (CRESST/GSFC/USRA), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU) and M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift Team: At 06:16:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source near the galactic center (trigger=547142). The BAT on-board calculated location is RA, Dec 268.413, -25.762 which is RA(J2000) = 17h 53m 39s Dec(J2000) = -25d 45' 41" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for a long image trigger, the rapidly available BAT light curve shows no significant structure. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 04:38 UT on 2013 February 04. There will thus be no XRT or UVOT data for this trigger before this time. The position of this source, 3.6 degrees from the Galactic center and 0.1 degrees from the Galactic plane, as well as its duration (>20 minutes in the discovery image) strongly implies that this is Galactic transient. We shall assign a name for this source after ground analysis produces a refined position. Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14153 SUBJECT: Swift Trigger 547142: MAXI/GSC upper limit DATE: 13/01/28 16:41:44 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (AGU), M. Serino, M. Sugizaki, K. Morihana, T. Yamamoto, J. Sugimoto, T. Takagi, T. Mihara, M. Matsuoka (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa (JAXA), N. Kawai, M. Morii, R. Usui, K. Ishikawa (Tokyo Tech), A. Yoshida, Y. Nakano (AGU), H. Tsunemi, M. Sasaki (Osaka U.), H. Negoro, M. Nakajima, M. Asada (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu, R. Sato, T. Kawamuro (Kyoto U.), Y. Tsuboi, M. Higa (Chuo U.), M. Yamauchi, Y. Nishimura, T. Hanayama, K. Yoshidome, Y. Ogawa (Miyazaki U.), K. Yamaoka (ISAS) report on behalf of the MAXI team: The MAXI/GSC scanned the field of a probable Galactic source triggered by Swift BAT (trigger=547142; Cumming et al. GCN Circ. 14151) at 05:07:27 (69 min before the trigger) and 06:40:08 (24 min after the trigger) UT on 2013-01-28. The durations of each scan were 44 and 46 sec. No obvious source was detected by MAXI/GSC at the flight location of BAT. The 3 sigma upper limits of each scan derived by the MAXI/GSC data are 6.8 and 8.1 x 10^-10 erg/cm2/s (4-10 keV). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14155 SUBJECT: Swift/BAT trigger 547142 is new source Swift J1753.7-2544 DATE: 13/01/29 18:40:34 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC), W. Baumgartner (CRESST/GSFC/UMBC), J. Cummings (CRESST/GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC), D. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU/GSFC), J. Tueller (GSFC), T. Ukwatta (MSU) We report a follow-up to Cummings et al, GCN Circ. 14151, which reported on a possible galactic transient as Swift/BAT trigger 547142. We now know that this is a new galactic transient source. The source, to which we give the name Swift J1753.7-2544, was first detected by the BAT on 2013 January 24 (MJD 56316) and has been mostly brightening ever since. The BAT rates in the 15-50 keV band have been Jan 24: 0.0050 ± 0.001 ct/s/cm^2 (23 mCrab) Jan 25: 0.0074 ± 0.001 ct/s/cm^2 (33 mCrab) Jan 26: 0.014 ± 0.002 ct/s/cm^2 (64 mCrab) Jan 27: 0.0090 ± 0.001 ct/s/cm^2 (41 mCrab) Jan 28: 0.017 ± 0.002 ct/s/cm^2 (80 mCrab) Jan 29: 0.017 ± 0.002 ct/s/cm^2 (80 mCrab) The best BAT position is: RA(J2000) = 268.429, Dec(J2000) = -25.742 RA = 17h 53m 43s, Dec = -25d 44' 31" Glon= 3.664, Glat = +0.099 The estimated error (statistical plus systematic) is 3 arc minutes (90% confidence) This position is derived from the BAT transient monitor. At 06:16:29 UT on February 28, 2013 (MJD 56320), Swift J1753.7-2544 triggered BAT in a 1280-second image trigger. On-board software identified it as a gamma-ray burst, but the Swift team suggested that it is more likely a galactic transient (Cummings et al, GCN Circ. 14151). Using the BAT event data set from T+165 to T+963, we report further analysis of Swift J1753.7-2544 The BAT ground-calculated position from the event data is RA, Dec = 268.429, -25.745 deg which is within 0.2 arcminutes of the BAT monitor position. The partial coding was 92%. The mask-weighted light curve shows no significant structure and an average count rate in the 15-100 keV band of roughly 0.03 ct/s/cm^2. The time-averaged spectrum from T+165 to T+963 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.07 +- 0.25. The fluence in the 15-150 keV band is 2.1 +- 0.3 x 10^-6 erg/cm2. (90% confidence level. Sakamoto et al (GCN Circ. 14153) reported no detection in MAXI (4-10 keV) during short observations near the time of the BAT trigger. A Swift target of opportunity observation has been requested. However, due to a Sun constraint, there will be no Swift XRT or UVOT observations before Feb. 4, 2013. The BAT hard X-ray transient monitor light curve for Swift J1753.7-2544 can be found at http://swift.gsfc.nasa.gov/docs/swift/results/transients/weak/SWIFTJ1753.7-2544/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14251 SUBJECT: Trigger 549841: Swift detection of SGR1806-20 DATE: 13/02/27 01:42:03 GMT FROM: David Palmer at LANL D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 01:21:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the known position of the Soft Gamma Repeater SGR 1806-20 (trigger=549841). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 272.183, -20.393 which is RA(J2000) = 18h 08m 44s Dec(J2000) = -20d 23' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peak structure with a duration of about 0.128 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 01:22:31.6 UT, 50.8 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 272.1635, -20.4104 which is equivalent to: RA(J2000) = 18h 08m 39.23s Dec(J2000) = -20d 24' 37.5" with an uncertainty of 3.1 arcseconds (radius, 90% containment). This location is 1.8 arcseconds from that of SGR 1806-20. UVOT took a finding chart exposure of 150 seconds with the White filter starting 53 seconds after the BAT trigger. No optical counterpart has been found in the initial data products. The 8'x8' region for the list of sources generated on-board covers SGR1806-20. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. BAT's most recent detection of a burst from this source was a month ago (2013-01-20), and a comparably-sized burst was most recently detected by BAT on 2010-03-26. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14252 SUBJECT: SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis DATE: 13/02/27 14:22:23 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) A. Y. Lien (NASA/GSFC/ORAU) (i.e. the Swift-BAT team): Using the data set from T-119 to T+183 sec from the recent telemetry downlink, we report further analysis of the outburst from SGR 1806-20 (trigger #549841) (Burrows, et al., GCN Circ. 14251). The BAT ground-calculated position is RA, Dec = 272.158, -20.399 deg which is RA(J2000) = 18h 08m 38.0s Dec(J2000) = -20d 23' 58.1" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a symmetrical peak with a total width of about 100 msec. T90 (15-350 keV) is 0.05 +- 0.01 sec (estimated error including systematics). There is no evidence of additional outbursts in the post 180 sec of the lightcurve at the 0.2 ph/cm2/sec 3-sigma upper limit. Several models are fit over a time-averaged spectrum from T-0.02 to T+0.04 sec. A simple power-law model shows the power law index of 2.43 +- 0.24 (chi squared 49.55 for 57 d.o.f.). The fluence in the 15-150 keV band is 2.1 +- 0.3 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.49 sec in the 15-150 keV band is 0.5 +- 0.1 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 8.24 +- 1.19 keV (chi squared 54.15 for 57 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 37.64 +- 11.54 keV (chi squared 45.71 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/549841/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14259 SUBJECT: Fermi GBM trigger 130301.638 is not GRB DATE: 13/03/05 19:54:36 GMT FROM: Shaolin Xiong at UAH Shaolin Xiong (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 383843922 (130301.638) at 15:18:39.090 UT on 01 March 2013, tentatively classified as a GRB, is in fact due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14304 SUBJECT: Swift-BAT trigger 551030 is not astrophysical DATE: 13/03/14 14:01:36 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC) on behalf of the Swift team report: Swift trigger 551030 was due to a noise fluctuation in the image domain near (10 arcmin) the catalog source NGC1097. This 10 arcmin distance, a low image significance (5.82 sigma), and the lack of an XRT source strongly indicate that this trigger is non-astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14345 SUBJECT: Swift Trigger 552142: a possible GRB DATE: 13/03/28 02:49:14 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), V. Mangano (INAF-IASFPA), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), M. H. Siegel (PSU), E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 02:13:57 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB (trigger=552142). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 270.747, +21.327, which is RA(J2000) = 18h 02m 59s Dec(J2000) = +21d 19' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows nothing significant as is typical for an image trigger. The XRT began observing the field at 02:16:10.7 UT, 133.1 seconds after the BAT trigger. No source was detected in 1.5 ks of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 136 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.11. Ground reprocessing of the immediately available BAT data found a decreased significance at the on-board detection location. This, along with the non-detection of a source in the XRT and UVOT data means that we cannot confirm that this is a true astrophysical event. A final determination of the reality of this source will require analysis of the full ground-linked data set. Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14349 SUBJECT: Swift Trigger 552142 is a noise event DATE: 13/03/28 14:05:17 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA) and V. Mangano (INAF-IASFPA) for the Swift team: Further analysis of the BAT and XRT event data for Swift trigger 552142 (Krimm et al, GCN 14345) shows that this event was a low-significance image trigger on noise. The analysis of 1.8 ks of XRT data did not reveal X-ray sources in the field down to a flux limit of 3 x 10^-13 erg cm^-2 s^-1 in the 0.3-10 keV band. Therefore this event is not a GRB or other astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14355 SUBJECT: Swift detection of IGR J18245-2452 DATE: 13/03/30 02:50:40 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), D. N. Burrows (PSU), V. D'Elia (ASDC), S. T. Holland (STScI), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 02:22:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located the recently-discovered source IGR J18245-2452 (ATel #4925, Eckert et al) (trigger=552336). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 276.104, -24.875 which is RA(J2000) = 18h 24m 25s Dec(J2000) = -24d 52' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, the immediately available lightcurve data shows no obvious variation. The XRT began observing the field at 02:25:32.34 UT, 190.7 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 276.13519, -24.86810 which is equivalent to: RA(J2000) = 18h 24m 32.45s Dec(J2000) = -24d 52' 05.2" with an uncertainty of 4.0 arcseconds (radius, 90% containment). This location is 104 arcseconds from the BAT onboard position, within the BAT error circle; and 8.7 arcseconds from the location of the center of globular cluster M28. The XRT position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 41.6 arcseconds from the center of the 1.4 arcminute INTEGRAL error circle, and therefore consistent with the source being IGR J18245-2452. This position is also 2.4 arcseconds from that of a known X-ray source: 1RXH J182432.6-245205 in the ROSAT ROSHRI catalogue. The catalogued count-rate of this source is equivalent to approximately 0.013 XRT count/sec; the mean count-rate in the promptly-available XRT data is 0.80 count/sec. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.73 x 10^21 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the U filter starting 868 seconds after the BAT trigger. No credible counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any counterpart in the sub-image. The 8'x8' region for the list of sources generated on-board covers 0.00% of the XRT error circle. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14396 SUBJECT: Trigger 553930: Swift detection of a possible flare from HR 5110 DATE: 13/04/19 17:54:44 GMT FROM: Hans Krimm at NASA-GSFC W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), S. T. Holland (STScI), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 17:24:37 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible trigger from the RS CVn flare star HR 5110 (trigger=553930). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 203.650, +37.239 which is RA(J2000) = 13h 34m 36s Dec(J2000) = +37d 14' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the BAT light curve does not show any significant features. The XRT began observing the field at 17:26:43.4 UT, 125.9 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 203.70026, 37.18112 which is equivalent to: RA(J2000) = 13h 34m 48.06s Dec(J2000) = +37d 10' 52.0" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 253 arcseconds from the BAT onboard position, outside the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 5.5 arcseconds from that of HR 5110. We note that the XRT data are highly affected by optical loading from the star, and therefore we cannot determine at this time if there is any enhanced X-ray emission detected from this source. UVOT took a finding chart exposure of 250 seconds with the UVW2 filter starting 123 seconds after the BAT trigger. No new source is detected in the initial data products. Analysis of the UVOT data is complicated by the presence of the 5th magnitude star HR 5110. Since this was a low-significance (6.0 sigma) image trigger, it is not possible to tell from the rapidly available BAT data whether or not this is a real event. Further information will be available once the full BAT data is available. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14402 SUBJECT: Swift Trigger 553930 is not an astrophysical source DATE: 13/04/19 22:48:50 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA) for the Swift Team In reviewing the Swift/BAT event data for Trigger 553930 (Baumgartner et al, GCN 14396) we see no signs of significant activity from the RS CVn flare star HR 5110. Therefore we conclude that Trigger 553930 was a noise event in chance coincidence with a catalog source and is not due to an astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14433 SUBJECT: Swift Trigger 554135 is probably not a GRB or transient DATE: 13/04/21 21:18:18 GMT FROM: David Palmer at LANL W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), S. R. Oates (UCL-MSSL), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 21:02:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located a peak in the resulting image (trigger=554135). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 235.706, +58.498 which is RA(J2000) = 15h 42m 49s Dec(J2000) = +58d 29' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is consistent with random variation. The XRT began observing the field at 21:03:36.4 UT, 86.4 seconds after the BAT trigger. No source was detected in 253 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 89 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Because BAT's detection was marginal, and XRT found nothing at the location, we believe that this is probably not a GRB. However, a final determination of the reality of the source will require the full downlinked dataset. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14443 SUBJECT: Trigger 554491: Swift detection of a spike possibly from Sgr A* DATE: 13/04/25 19:49:55 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC) and A. Maselli (INAF-IASFPA) report on behalf of the Swift Team: At 19:15:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located a transient position consistent with Sgr A* (trigger=554491). Swift did not slew immediately because the current target had a higher merit value. The slew was delayed by 15 min. The BAT on-board calculated location is RA, Dec 266.412, -28.990 which is RA(J2000) = 17h 45m 39s Dec(J2000) = -28d 59' 22" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows shows a single 64 msec bin. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. The BAT position is within 65 arcsec of the galactic center and Sgr A*. Given the recent activity reported from Sgr A* (ATEL #5006), it's quite possible that this is the source of X-ray flaring. Also, this is a confused region, so we cannot rule out other candidates. The XRT began observing the field at 19:31:27.6 UT, 962.8 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 266.41715, -29.00866 which is equivalent to: RA(J2000) = 17h 45m 40.12s Dec(J2000) = -29d 00' 31.2" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 69 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.2 arcseconds from that of Sgr A*, and is consistent with being that source. The X-ray source shows an elevated emission level, consistent with that reported from observations taken yesterday in ATEL #5006. UVOT took a finding chart exposure of 150 seconds with the White filter starting 967 seconds after the BAT trigger. No credible optical counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14512 SUBJECT: Swift-BAT trigger 554135 is noise DATE: 13/04/30 13:36:38 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), P.A. Evans, and K.L. Page (U. Leicester) (on behalf of the Swift team): Using the data set from T-240 to T+963 sec from telemetry downlinks, we report further analysis of BAT trigger #554135 (Baumgartner, et al., GCN Circ. 14433). This trigger is due to noise in the BAT image domain. There is no XRT source in the BAT error circle. It is not astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14551 SUBJECT: Trigger 555096: Swift detection of a possible burst DATE: 13/05/04 02:29:39 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 02:05:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger=555096. Swift slewed immediately to the transient. The BAT on-board calculated location is RA, Dec 272.365, -16.344 which is RA(J2000) = 18h 09m 27s Dec(J2000) = -16d 20' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two FRED peaks with a duration of about 25 sec. The peak count rate was ~1617 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 02:07:00.2 UT, 85.9 seconds after the BAT trigger. No source was detected in 1.1 ks of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 88 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The event is unusual in that it is a long burst in BAT with no detected X-ray counterpart after an immediate slew. We also note that this location is in the Galactic bulge near the plane (lon = 13.65, lat=1.56). Ground analysis of the detector plane histogram finds only a marginal image detection (5.9 sigma). For these reasons, we will not be able to determine the reality or nature of this event until ground-linked data is available. Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14610 SUBJECT: Fermi Trigger 130507.091 - Detection of a SGR-like Burst DATE: 13/05/08 20:29:58 GMT FROM: Andrew Collazzi at NASA/MSFC/ORAU Andrew C Collazzi (NASA/ORAU), George Younes (NASA/USRA) and Chryssa Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM-Magnetar Team. "At 02:11:29.43 UT on 7 May, 2013, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located an SGR-like burst (trigger 389585492 / 130507.091). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 281.22, Dec = -2.12 (J2000 degrees, equivalent to J2000 18h 45m, -2d 7'), with a statistical uncertainty of 8.9 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The 3-sigma error region for the burst contains several known magnetars, but does not include the recently discovered magnetar at the galactic center, SGR J1745-29 (Atel #5020). The burst consists of a single pulse with a duration of T90 = 20 +/- 9 ms. The burst spectrum is adequately fit by a single blackbody with a kT = 9.8 +/- 0.7 keV. The corresponding peak flux integrated over 4ms (8-200 keV) is (2.2 +/- 0.4)E-06 erg/s/cm^2. The fluence during T0-0.020s to T0+0.016s is (3.8 +/- 0.4)E-8 erg/cm^2. The analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14651 SUBJECT: 130514B: Swift-XRT Observations DATE: 13/05/15 02:12:20 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU), Dirk Grupe (PSU) and D. Malesani (DARK/NBI) report on behalf of the Swift-XRT team: We have analyzed 2.0 ks of XRT data for the INTEGRAL-detected burst: GRB 130514B, from 5.0 ks to 10.8 ks after the INTEGRAL trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the INTEGRAL error circle. Using 1475 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 147.60859, -18.96517 which is equivalent to: RA (J2000): 09h 50m 26.06s Dec(J2000): -18d 57' 54.6" with an uncertainty of 1.8 arc sec (radius, 90% confidence). This position is 37 arcsec from the INTEGRAL position. The X-ray source was detect with a peak count rate of 0.31 count/s at ~ T0+5359s, where T0= 2013 May 14 at 13:26:29.510 UT, then faded to a count rate of 0.11 count/s at T0+11 ks. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.17 (+0.31, -0.30). The best-fitting absorption column is 3.6 (+1.2, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 3.6 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (7.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.6 (+1.2, -1.1) x 10^21 cm^-2 Galactic foreground: 3.6 x 10^20 cm^-2 Excess significance: 5.0 sigma Photon index: 2.17 (+0.31, -0.30) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020275. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14664 SUBJECT: Fermi GBM trigger 390275038 / 130515072 is not a GRB DATE: 13/05/15 18:56:33 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH), reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 390275038 / 130515072 at 01:43:55.53 UT on 15 May 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to an X-class solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14699 SUBJECT: Swift Trigger 556533 is probably not an astrophysical event DATE: 13/05/24 04:23:05 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 04:03:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 556533. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 118.580, -28.134 which is RA(J2000) = 07h 54m 19s Dec(J2000) = -28d 08' 03" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed no significant structure. The peak count rate was ~1400 counts/sec (15-350 keV), at ~4 sec after the trigger. The XRT began observing the field at 04:05:29.5 UT, 94.7 seconds after the BAT trigger. No source was detected in 574 s of promptly downlinked data, which covered 92% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of nominal 250.000 seconds with the U filter starting 154 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This was a marginal detection (5.85 sigma) in an image at a location which was almost 12 arcminutes from the known source A0753-2802. Under these circumstances, Swift attempts to verify or refute the reality of the possible event using the narrow field instruments. In this case, we believe that this was due to a statistical fluctuation and not an astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14701 SUBJECT: Swift Trigger 556533 is not an astrophysical event DATE: 13/05/24 14:04:50 GMT FROM: Hans Krimm at NASA-GSFC S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), and M. H. Siegel (PSU) report on behalf of the Swift Team: We conclude that subthreshold trigger #556533 (Beardmore, et al., GCN Circ. 14699) was caused by a cosmic ray shower and chance coincidence and is not due to a GRB or other astrophysical phenomenon. Using the data set from T-240 to T+963 sec from the recent telemetry downlink, we report that the full Swift/BAT event data shows no significant features in the light curve. The Swift/XRT began settled observations of the field of trigger #556533 155 s after the BAT trigger. There is nothing visible in the XRT data at the position of the BAT onboard error circle, or in the entire image. The XRT upper limit is 0.01 c/s in 614 s of PC mode data. The Swift/UVOT began settled observations of the field of trigger #556533 155 s after the BAT trigger. No optical afterglow consistent with the BAT position is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u_FC 155 405 246 >19.7 v 460 629 39 >18.3 b 410 724 55 >19.1 u 155 703 285 >19.7 w1 510 678 39 >18.2 w2 584 604 19 >17.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.85 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14767 SUBJECT: Swift Trigger 557466 is probably not real. DATE: 13/06/05 09:23:11 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst M. Stamatikos (OSU/NASA/GSFC), M. M. Chester (PSU), S. T. Holland (STScI), D. Malesani (DARK/NBI), A. Melandri (INAF-OAB), T. Sakamoto (AGU), R. L. C. Starling (U Leicester) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team: At 08:47:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 557466. Swift slewed immediately to the trigger location. The BAT on-board calculated location is RA, Dec 53.405, -31.355 which is RA(J2000) = 03h 33m 37s Dec(J2000) = -31d 21' 16" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the currently available BAT light curve does not show much structure. This trigger was a sub threshold trigger (6.1 sigma significance), and is spatially coincident with a nearby galaxy (10.2 arc minutes from NGC 1366). Further analysis of data on the ground will be required to verify the reality of this event. The XRT began observing the field at 08:49:37.2 UT, 123.9 seconds after the BAT trigger. No source was detected in 987 s of promptly downlinked data, which covered 90% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 128 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Given the low significance and the lack of an XRT counterpart, we cannot assess whether this trigger is real. We are waiting for the download of the full dataset to undertake further analysis. Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14786 SUBJECT: Swift Trigger 557466 is not astrophysical DATE: 13/06/06 23:12:34 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) and P.A. Evans (U. Leicester), on behalf of the Swift Team report: Using the BAT data set from T-119 to T+183 sec from recent telemetry downlinks, we report on further analysis of BAT trigger #557466 that the trigger is not due to anything astrophysical. It was a chance coincidence of noise in the image domain and a known source. Analysis of 1 ks of XRT reveals no source in or near the BAT error circle. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14805 SUBJECT: Trigger 557640: Swift detection of burst from SGR J1745-29 DATE: 13/06/07 11:57:22 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC) and J. A. Kennea (PSU) report on behalf of the Swift Team: At 11:17:26 UT, the Swift Burst Alert Telescope (BAT) triggered on an outburst from SGR J1745-29 (trigger=557640). Swift did not slew to the source because of the existence of a higher-merit automated target. There will be no XRT or UVOT data on this event. The BAT on-board calculated location is RA, Dec 266.433, -28.992 which is RA(J2000) = 17h 45m 44s Dec(J2000) = -28d 59' 32" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single soft peak with a duration of < 0.32 sec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~0 sec after the trigger. After the trigger on April 25th (Barthelmy et al, GCN #14443), this is the second burst from SGR J1745-29 detected by BAT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14821 SUBJECT: Swift Trigger 557674 is a probable new Galactic transient DATE: 13/06/08 01:04:36 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. R. Cummings (NASA/UMBC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), D. Malesani (DARK/NBI) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 00:16:37 UT, the Swift Burst Alert Telescope (BAT) triggered and located a likely new galactic transient source (trigger=557674). The BAT on-board calculated location is RA, Dec 256.064, -37.457 which is RA(J2000) = 17h 04m 15s Dec(J2000) = -37d 27' 24" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The full BAT light curve is not yet available so we cannot say anything about its structure. Since the source is near the galactic plane glon=348.10, glat=+2.36 and is of very long duration (768 seconds), we do not believe that it is a GRB, but rather it is likely to be a new galactic transient. We also note that the source identified in the original GCN alert is more than a degree away from the trigger position, so is most likely not the source of the trigger. Due to an observing constraint, the slew to this target was delayed. We will report on XRT and UVOT observations in a later GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14825 SUBJECT: Swift Trigger 557674 was due to an onboard position error DATE: 13/06/08 15:53:10 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (UMBC/CRESST/GSFC) reports on behalf of the Swift team: The probable new Galactic transient reported in GCN Circular # 14821 was not a new source. It was a known source (4U 1700-377) reported in an incorrect position. The cause of the error of ~0.4 degrees is not yet known. The Swift star tracker was correctly locked during the observation and the source was found in the correct position in all image sub-intervals that made up the summed image interval that resulted in the erroneous report. We regret any inconvenience. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14873 SUBJECT: Recent Fermi GBM particle triggers misclassified as GRBs DATE: 13/06/11 16:57:34 GMT FROM: Hoi-Fung Yu at MPE Subject: Recent Fermi GBM particle triggers misclassified as GRBs Hoi-Fung Yu (MPE) and J. Michael Burgess (UAH) report on behalf of the Fermi GBM Team: "The 3 recent Fermi GBM triggers, 391784867 / 130601547 at 13:07:44.36 UT on 1 June 2013, 392214373 / 130606518 at 12:26:10.61 UT on 6 June 2013, and 392220367 / 130606588 on at 14:06:04.93 UT 6 June 2013, tentatively classified as GRBs, are in fact not due to GRBs. These triggers are due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14910 SUBJECT: Swift Trigger 557910 is not astrophysical DATE: 13/06/16 22:17:45 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC), J.R. Cummings (GSFC/UMBC) and C.B. Markwardt (GSFC) on behalf of the Swift Team report: Using the data set from T-116 to T+49 sec from recent telemetry downlinks, we report on further analysis of BAT trigger #557910 that the trigger is not due to anything astrophysical. The trigger was caused by incorrect spacecraft attitude information applied to a known source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14911 SUBJECT: Trigger 558399: Swift detection of the Soft Gamma Repeater AXP 1E1547.0-5408 DATE: 13/06/17 10:28:00 GMT FROM: David Palmer at LANL S. T. Holland (STScI), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), T. Sakamoto (AGU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 09:52:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Soft Gamma Repeater AXP 1E1547.0-5408 (trigger=558399). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 237.714, -54.277 which is RA(J2000) = 15h 50m 51s Dec(J2000) = -54d 16' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single spike structure with a duration of about 0.2 sec. The peak count rate was ~8570 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 09:53:41.8 UT, 71.8 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 237.7266, -54.3063 which is equivalent to: RA(J2000) = 15h 50m 54.39s Dec(J2000) = -54d 18' 22.6" with an uncertainty of 2.7 arcseconds (radius, 90% containment). This location is 108 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.8 arcseconds from that of AXP 1E1547.0-5408. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 75 seconds after the BAT trigger. No credible counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This soft gamma repeater had a major period of activity in October, 2008 (ATEL #1756, Rea et al., 2008) and was last seen by Swift BAT on 2011-12-20. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14912 SUBJECT: Fermi/GBM observation of the Soft Gamma Repeater SGR J1550-5418 DATE: 13/06/17 16:32:52 GMT FROM: David Gruber at MPE David Gruber (MPE) reports on behalf of the Fermi GBM Team: "At 09:52:30.48 UT on 17 June 2013, the Fermi Gamma-Ray Burst Monitor triggered on a burst from SGR J1550-5418 / AXP 1E1547.0-5408 (trigger 393155553 / 130617411) which was also detected by the Swift satellite (Holland et al. 2013, GCN 14911). The GBM on-ground location is consistent with the Swift position. The GBM light curve consists of a single pulse with a duration (T90) of about 0.2 s (8-200 keV). The time-averaged spectrum from T0-0.24 s to T0-0.032 s is best fit by a blackbody function with a kT = 12.9 +/- 0.6 keV. The event fluence (10-1000 keV) in this time interval is (1.3 +/- 0.1)E-07 erg/cm^2. The 16 ms peak photon flux measured at T0-0.208 s in the 10-1000 keV band is 19.8 +/- 2.6 ph/s/cm^2. The spectral analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14917 SUBJECT: Swift Trigger 558631 is not a real source DATE: 13/06/20 10:53:11 GMT FROM: David Palmer at LANL B. N. Barlow (PSU), D. N. Burrows (PSU), S. T. Holland (STScI), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), C. A. Swenson (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 02:21:57 UT, the Swift Burst Alert Telescope (BAT) triggered on a likely noise fluctuation (trigger=558631). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 271.805, -22.291, which is RA(J2000) = 18h 07m 13s Dec(J2000) = -22d 17' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Since it is an image trigger, the light curve shows no significant features. The XRT began observing the field at 02:29:59.5 UT, 482.3 seconds after the BAT trigger. No source was detected in 376 s of promptly downlinked data, which covered 39% of the BAT error circle. UVOT took a finding chart exposure of 150 seconds with the White filter starting 486 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This was a marginal significance (5.8 sigma) image peak which was within 0.2 degrees (actual distance 0.176 degrees) of a known source. Under this set of conditions, Swift is programmed to slew to determine the reality of the detection using the XRT and UVOT. Due to the lack of an XRT detection, and the lack of a rate trigger, we believe that this is a statistical fluctuation and not a real source detection. [GCN OPS NOTE(20jun13): This Circular was delayed in distribution (~8 hrs) because none of the "magic" strings (eg "GRB", "Swift") was present in the Subject-line.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14919 SUBJECT: Swift Trigger 558631: AAO optical observations DATE: 13/06/22 13:42:50 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (IKI), R.Inasaridze (AAO), O. Kvaratskhelia (AAO), V. Ayvazian(AAO), Yu. Krugly (IA KhNU), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: Following trigger Swift #558631 (Barlow et al., GCN 14917) we imaged the region of the trigger with starting on June 21 (UT) 19:54:46. We obtained 50 unfiltered images of 50 s exposure. We investigated a combined image (mid time after the Swift trigger 0.75693 days) and within BAT error circle (Barlow et al., GCN 14917) found one bright source which is not catalogued in USNO-B1.0 but barely visible in DSS2 Red image. Coordinates of the source is (J2000) 18:07:13.13 -22:17:14.4. It is apparent that the source is not coincident with known X-ray source SAX_J1806.5-221. Brightness of the source is 17.09 +/- 0.03 calibrating against nearby USNO-B1.0 stars (R2). At present time it is not clear if the source is related to the Swift #558631 trigger. The source also can be a new cataclysmic variable with magnitude of the outburst of ~3m. A finding cahart can be found in http://grb.rssi.ru/Swift_558631/Swift_558631_chart.png //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14920 SUBJECT: Swift Trigger 558828 is not an interesting event DATE: 13/06/23 09:16:07 GMT FROM: David Palmer at LANL D. Malesani (DARK/NBI), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: Due to a known race condition in the Swift software, an image peak was misidentified as a rarely-seen source. It was, however, correctly identified on the ground as 4U 1700-377, at a flux level that is often seen for this source. Thus this detection is not an interesting event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14932 SUBJECT: Swift Trigger 559108 is not astrophysical DATE: 13/06/26 21:43:03 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT N. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC) and S. R. Oates (UCL-MSSL) report on behalf of the Swift Team: At 21:08:37 UT, the Swift Burst Alert Telescope (BAT) triggered on trigger=559108. Swift slewed immediately to the location. However, we believe that this was an erroneous trigger on a bright source for which the BAT flight software used the incorrect attitude. Therefore, we believe that trigger 559108 is neither a GRB nor the catalog source IGR_J11215-5952, nor any other astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14946 SUBJECT: Swift trigger 559221 is likely a false trigger coincident with IGR J17544-2619 DATE: 13/06/28 08:00:32 GMT FROM: Samantha Oates at MSSL V. D'Elia (ASDC), A. Y. Lien (NASA/GSFC/ORAU), D. Malesani (DARK/NBI), S. R. Oates (UCL-MSSL), K. L. Page (U Leicester) and P. Romano (INAF-IASFPA) report on behalf of the Swift Team: At 07:26:21 UT, the Swift Burst Alert Telescope (BAT) triggered (559221) on a noise fluctuation in the image domain which we likely believe was a chance coincidence with the source IGR J17544-2619 in the on-board catalog. As is typical for image triggers (64 sec, image significance=6.02 sigma), the real-time TDRSS lightcurve does not show anything significant. The XRT began observing the field at 07:28:32.9 UT, 131.7 seconds after the BAT trigger. XRT initially centroided on the IGR source IGR J17544-2619, however this is 378 arcseconds from the BAT position, well outside the BAT error circle. No source was found in the BAT error circle in 480 s of promptly-downlinked event data. UVOT took a finding chart exposure of 250 seconds with the U filter starting 137 seconds after the BAT trigger. No credible new source has been found in the initial data products. The overlap of the 8'x8' region for the list of sources generated on-board and the BAT error circle is 100%. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14965 SUBJECT: Fermi GBM trigger 394325281 / 130630950 is not a GRB DATE: 13/07/02 15:30:24 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 394325281 / 130630950 at 22:47:58.42 UT on 30 June 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14967 SUBJECT: Fermi394416326: iPTF detection of a possible optical afterglow DATE: 13/07/03 08:24:18 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), S. B. Cenko (NASA/GSFC), M. M. Kasliwal (Carnegie Observatories), D. A. Brown (Syracuse), O. Yaron (Weizmann Institute of Science), E. Bellm (Caltech), S. Caudill (Milwaukee), S. Tinyanont (Harvey Mudd), D. Khatami (Pomona), and A. J. Weinstein (Caltech) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: We have imaged 72 deg^2 of the vicinity of the final localization of the Fermi-GBM trigger 394416326 with the Palomar 48 inch Oschin telescope (P48). Images were obtained in the Mould R filter in 2 visits to each of 10 fields. Within the GBM error circle, we detect a bright point source at the position: RA(J2000) = 14h 29m 14.78s DEC(J2000) = +15d 46' 26.4" which is 3.8 degrees away from the center of the final GBM localization (68% confidence radius of 3.99 degrees). At 04:17 UT on 2013 July 2 (4.2 hours after the Fermi-GBM trigger), we measure a magnitude of R = 17.4 for the source, dubbed iPTF13bxl. Nothing was detected at this location in previous P48 images of the field taken on 2011 February 5 to a limiting magnitude of R > 21.1. Automatic follow-up of iPTF13bxl was obtained with the robotic Palomar 60 inch telescope beginning at 4:10 UT on 2013 July 3 (28.1 hours after the burst trigger). At this time we measure a magnitude of r' = 18.7. Assuming the source decays as a single power-law from the time of our P48 to discovery to this time, we infer a decay index of 0.54. We observed iPTF13bxl with the Double Beam Spectrograph on the Palomar 200-inch (P200) on 2013-07-03 04:24:04, 28.3 hours after the burst. The spectrum has a largely featureless blue continuum with no strong, narrow features in emission or absorption between 3800A and 9000A. We triggered target-of-opportunity observations of iPTF13bxl with the Swift satellite, beginning at 00:50 UT on 2013 July 3 (1.03 d after the Fermi-GBM trigger). A total exposure time of 1.4 ks was obtained with the on-board X-Ray Telescope (XRT). A bright source is detected at the location of iPTF13bxl in the XRT. We measure a preliminary count rate of 0.3 ct s^-1 at this time. Assuming a power-law spectrum with a photon index of 2, this corresponds to a 0.3-10.0 keV X-ray flux of ~ 10^-11 erg cm^-2 s^-1. We note that close to iPTF13bxl are two SDSS sources: SDSS J142914.75+154626.0, at a separation of 0.6", a faint source classified as a star with r = 23.01, and SDSS J142914.57+154619.3, at a separation of 7.6", a bright galaxy with a photometric redshift of 0.09 +/- 0.02. Without a secure spectroscopic redshift, we cannot definitively associate this source with the Fermi-GBM GRB. The bright X-ray emission and relatively steep decay in the optical seem to rule out an (unrelated) supernova, but other potential interlopers remain. Follow-up observations are ongoing and encouraged to help identify the nature of this source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14968 SUBJECT: Fermi394416326: FTN detection DATE: 13/07/03 10:02:32 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (Ferrara U.), C.G. Mundell, I.A. Steele (LJMU), on behalf of a large collaboration report: On 2013 July 03 (09:03:30 UT) we began observing the field of the possible optical afterglow of Fermi394416326 (Singer GCN Circ. 14967) with the 2-m Faulkes Telescope North in Hawaii. Observations were carried out using the BVRi filters. We clearly detect the optical counterpart discovered by Singer et al. with the following magnitudes Time from GRB Filter Exposure[s] Magnitude (days) ---------------------------------------------------- 1.38 i' 100 18.61 +- 0.07 1.38 R 120 18.46 +- 0.05 ---------------------------------------------------- The calibration was performed using the i' magnitudes of SDSS catalogue field stars and the R magnitudes obtained using the transformations by Jordi et al (2006). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14970 SUBJECT: Fermi GBM trigger 394416326: MASTER early optical limit DATE: 13/07/03 16:24:15 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs H. Levato and C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) C. Mallamaci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA) E. Gorbovskoy, D. Denisenko, V. Lipunov, V. Kornilov, A. Kuznetsov, D. Kuvshinov, N. Tyurina, N. Shatskiy, P. Balanutsa, D. Zimnukhov, V.V. Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute A. Tlatov, A.V. Parhomenko, D. Dormidontov, V. Sennik Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, S. Yazev, N.M. Budnev, O. Gres, O. Chuvalaev, V.A. Poleshchuk Irkutsk State University V. Yurkov, Yu. Sergienko, D. Varda, E. Sinyakov Blagoveschensk Educational State University, Blagoveschensk V. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University MASTER-ICATE robotic very wide field cameras (FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec, http://observ.pereplet.ru) located in Argentina (Observatorio Astronomico Felix Aguilar, http://master.sai.msu.ru:8080/) were pointed to the Fermi-GBM trigger 394416326 55 sec after GRB time and 49 sec FERMI trigger Time at 2013-07-02 00:06:18 UT. We haven't found optical transient (Singer et. al. GCN 14967) on single (exp = 5 sec) images with upper limit V<11m and coadded image made of first 58 frames (5 sec exposure without time gap) and total exposure of 290 seconds with upper limit V<12.5m. Our magnitudes are calibrated against V magnitudes from Tycho-2 catalog. This upper limit does not contradict the power law decay with an index of 0.54 inferred by Singer et al. in GCN 14967. The reduction of the whole data set is continuing. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14988 SUBJECT: GRB DATE: 13/07/05 14:48:13 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), A. Volnova (IKI), O. Burhonov (UBAI), I. Molotov (KIAM) report on behalf GRB follow-up collaboration: We observed the field of OT (Singer et al., GCN 14967) of GRB 130702Ð (= Fermi 394416326)(Cheung et al., GCN 14971; Collazzi et al., GCN 14972) with AZT-22 telescope of Maidanak observatory on Jul. 3 and Jul. 4 under good weather conditions and seeing (FWHM) of about 1 arcsec. We clearly detected OT (Singer et al., GCN 14967) in each images of both epochs. A preliminary photometry of combined images is based on the two SDSS stars suggested by Schulze et al. (GCN 14978), i.e. SDSS J142915.86+154510.0 assuming R = 16.03 SDSS J142911.60+154535.2 assuming R = 15.59 T_start T0+ Filter, Exposure, OT (UT) (mid, d) (s) 2013-07-03T17:38:18 1.70828 R 6x600 18.69 +/- 0.03 2013-07-04T16:49:20 2.67427 R 6x300 19.31 +/- 0.04 We note that the fading of a lc assuming a power law between our two epochs is alpha=1.27 which is steeper, than reported in early observations (Perley et al., GCN 14981). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15026 SUBJECT: Swift Trigger 563980 cannot be identified at this time. DATE: 13/07/25 12:29:46 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), M. M. Chester (PSU), D. Grupe (PSU), D. M. Palmer (LANL), P. Romano (INAF-IASFPA) and B.-B. Zhang (PSU/UAH) report on behalf of the Swift Team: At 11:37:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located an unknown source (trigger=563980). This occurred during an episode of intermitant TDRSS connection, so most of the telemetry messages were not received. Swift did not slew to the source. Due to the telemetry gaps, we will not know the location or the characteristics of this source until ground-linked data is available. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15027 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 396447899 / 130725517 is not a GRB DATE: 13/07/25 14:31:02 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 396447899 / 130725517 at 12:24:56.76 UT on 25 July 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15037 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 396533554 / 130726509 is not a GRB DATE: 13/07/26 12:35:39 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) 396533554 / 130726509 at 12:12:31.53 UT on 26 July 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15043 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 396484884 / 130725945 is not a GRB DATE: 13/07/26 16:35:52 GMT FROM: George A. Younes at USRA/NASA/MSFC George A. Younes (USRA/MSFC) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) 396484884 / 130725945 at 22:41:21.34 UT on 25 July 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a Solar Flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15069 SUBJECT: Trigger 565443: Swift detection of a burst from SGR J1745-29 DATE: 13/08/05 02:43:52 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), V. Mangano (PSU), C. J. Mountford (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 02:09:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst consistent with the location of the Soft Gamma Repeater SGR J1745-29. Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 266.420, -29.004 which is RA(J2000) = 17h 45m 41s Dec(J2000) = -29d 00' 14" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short soft peak with a duration of 64 ms. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 02:10:11.0 UT, 61.2 seconds after the BAT trigger. Using promptly downlinked data we detect several x-ray sources as expected for the Galactic Center region. Further analysis using the full data will be required to identify the source of this event. UVOT took a finding chart exposure of 150 seconds with the White filter starting 66 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. We believe that this is further activity from the SGR J1745-29 source which BAT last detected on June 7 of this year. (The Chandra location of this source is given in ATEL #5032.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15074 SUBJECT: SGR 1745-29 (Swift trigger 565443), Swift-BAT refined analysis DATE: 13/08/06 12:14:47 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-120 to T+182 sec from the recent telemetry downlink, we report further analysis of the burst from SGR 1745-29 (trigger #565443) (Barthelmy, et al., GCN Circ. 15069). The BAT ground-calculated position is RA, Dec = 266.403, -29.017 deg which is RA(J2000) = 17h 45m 36.8s Dec(J2000) = -29d 01' 02.3" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single peak with some substructure at low significance. T90 (15-350 keV) is 0.011 +- 0.002 sec (estimated error including systematics). The time-averaged spectrum from T+0.00 to T+0.01 sec is best fit by functions exponentially declining with energy in the BAT energy range. A blackbody fit is formally the best fit with kT = 8.9 +/- 0.2. A simple powerlaw fit has a power law index of the time-averaged spectrum of 2.54 +- 0.26. The fluence in the 15-150 keV band is 9.2 +- 1.6 x 10^-09 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 22.1 +- 3.6 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/565443/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15109 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 398555975 / 130818916 is not a GRB DATE: 13/08/19 00:17:27 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 398555975 / 130818916 at 21:59:32.73 UT on 18 August 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15111 SUBJECT: GRB 130816A: Swift/UVOT Upper Limits DATE: 13/08/19 19:49:29 GMT FROM: Stephen Holland at STScI S. T. Holland (STScI) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130816A starting 91 s after the BAT trigger (Holland et al. 2013, GCNC 15097). We do not detect any new source consistent with the REM afterglow position (Covino et al. 2013, GCNC 15098) in any of the UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the finding chart (FC) exposures and initial summed exposures are presented below. --------------------------------------------------- Filter TSTART TSTOP Exposure Mag --------------------------------------------------- white (FC) 91 241 147 >20.8 u (FC) 303 554 246 >19.9 --------------------------------------------------- v 633 1924 156 >19.2 b 559 1850 136 >20.0 u 707 1825 117 >19.5 uvw1 682 1801 117 >19.3 uvm2 658 1944 151 >19.4 uvw2 609 1900 156 >19.7 white 584 1875 284 >21.1 --------------------------------------------------- The quoted upper limits have not been corrected for the expected extinction due to the Galactic reddening along the line of sight to this burst of E(B-V) = 0.70 mag (Schlafly et al. 2011, ApJS, 737, 103). GRB 130816A was 4 degrees above the Galactic Plane, so this extinction value is highly uncertain. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15157 SUBJECT: Swift Trigger 569022: a possible GRB DATE: 13/09/01 09:39:14 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), D. Grupe (PSU), C. J. Mountford (U Leicester), M. H. Siegel (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 09:13:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located possible GRB 130901A or a Galactic source (trigger=569022). Swift slewed immediately to the detected source position. The BAT on-board calculated location is RA, Dec 263.611, -30.402 which is RA(J2000) = 17h 34m 27s Dec(J2000) = -30d 24' 07" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve does not show significant variation, which is not unusual for an image-based trigger. The XRT began observing the field at 09:15:20.0 UT, 123.0 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 263.6018, -30.3961 which is equivalent to: RA(J2000) = +17h 34m 24.43s Dec(J2000) = -30d 23' 46.0" with an uncertainty of 5.3 arcseconds (radius, 90% containment). This location is 35 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 0.1 s image was 3.68e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 4 seconds with the White filter starting 131 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image cover 100% of the XRT error circle. Results from the list of sources generated on-board are not available at this time. This burst occurred at Galactic coordinates l = 357.47, b = 1.29, that is only 2.8 deg away from the Galactic Center. At this stage, we cannot confirm whether this is a Galactic or extragalactic transient. Burst Advocate for this burst is D. Malesani (malesani AT dark-cosmology.dk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15172 SUBJECT: Swift trigger 569022 is a new Galactic source Swift J1734.5-3027 DATE: 13/09/03 17:12:33 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), J. A. Kennea, D. N. Burrows (PSU), J. R. Cummings (GSFC/UMBC), C. B. Markwardt, N. Gehrels (GSFC), T. N. Ukwatta (MSU), B. Sbarufatti (PSU), C. J. Mountford (Leicester), H. A. Krimm (GSFC/USRA), M. H. Siegel, M. M. Chester, D. Grupe (PSU), report: The Swift team has carried out further analysis of trigger 569022 (Malesani et al., GCN 15157; Kennea et al., ATel 5354). The BAT emission is extremely soft, and using the full data set the spectrum is best fit with a black body function with a temperature of 2.57+-0.22 keV (reduced chi^2 = 0.79, where the small value is due to allowances for systematic errors). The best fit simple power law (reduced chi^2 = 0.93) has a photon index of 5.87+-0.43. The X-ray light curve shows an initial decay with very prominent dips (by a factor of 10 in flux), and is observed to rise starting around 60 ks after the trigger. The time-averaged spectrum during the first orbit is not well fit by an absorbed power law, but can be described with an absorbed black-body model with kT = 1.50+-0.02 keV and N_H = (0.67+-0.05)*10^22 cm^-2. UVOT detected no bright counterpart, which is expected given the large Galactic extinction towards this sightline. Given the above properties, unusual among cosmic GRBs, and the position 2.8 deg away from the Galactic centre, we conclude that the trigger is not due to a GRB, but is a new Galactic transient that we name Swift J1734.5-3027 (Kennea et al., ATel 5354). Automatic BAT and XRT products are available at the following URLs: http://gcn.gsfc.nasa.gov/notices_s/569022/BA/ http://www.swift.ac.uk/possible_GRBs/00569022/source1 This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15180 SUBJECT: Swift follow-up of an INTEGRAL possible weak GRB DATE: 13/09/04 21:07:26 GMT FROM: Margaret Chester at PSU R.L.C. Starling (U. Leicester), F.E. Marshall (NASA/GSFC), M.M. Chester (PSU), and M. De Pasquale (UCL-MSSL) report on behalf of the Swift team: Swift began a target of opportunity observation (target ID 20296) of INTEGRAL Weak Alert #6931/0 on September 4, 2013 at 18:37 UT, approximately 2 hours after the possible burst was detected by INTEGRAL. Its INTEGRAL coordinates are RA = 256.876 deg, Dec = -32.011 deg, with an error of 3.6 arcminutes (see http://www.ncac.torun.pl/~jubork/ibas/ibas?onlyyear=2013&onlymonth=9&slcn=weak). The XRT began observing the field at 18:39:03.9 UT, 7.2 ks after the INTEGRAL trigger. No source was detected in 2.3 ks of promptly downlinked SPER data. We are waiting for the full 6 ks dataset to detect any source. UVOT took a finding chart exposure of 150 seconds with the White filter starting 7170 seconds after the INTEGRAL trigger. No credible afterglow candidate has been found in the initial data products. Because of the density of catalogued stars, further analysis is required to report an upper limit for any new source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15182 SUBJECT: Swift follow-up results of the possible weak INTEGRAL GRB DATE: 13/09/06 14:01:35 GMT FROM: Rhaana Starling at U of Leicester Rhaana Starling (U. Leicester) reports on behalf of the Swift team We report further analysis of Swift follow-up of the possible weak INTEGRAL GRB detected on 4th September 2013 (GCN 15180). The full XRT dataset, comprising 6.28 ks of exposure and beginning 2 hours after the INTEGRAL detection, shows no evidence for a source at the INTEGRAL Weak alert position. The 3-sigma upper limit on the count rate at this position, using Bayesian statistics (Kraft, Burrows & Nousek 1991), is 2.2e-3 count/s. We do find a new X-ray source at position RA (J2000) = 17 08 03.52 Dec (J2000) = -32 02 31.5 or RA, Dec = 257.0147, -32.0421 degrees with an uncertainty of 3.9 arcseconds (radius, 90% confidence). This is 7.3 arcminutes from the INTEGRAL position, and lies outside the given 3.6 arcminute radius error circle. This source is 4.9-sigma significant, and has a count rate of (4.4 +3.6/-2.5)e-3 count/s. A source is listed at this position in a number of optical and nIR surveys, and in the Atlas of Radio/X-ray associations (Flesch 2010) where it is classified as a double radio lobe. Three further low-significance (=<3-sigma) sources are present in the field. The association of any of these with the INTEGRAL trigger is unclear. No further Swift observations of this source are planned at this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15228 SUBJECT: Fermi/GBM Detection of two SGR-like bursts possibly associated with SGR J1833-0832 DATE: 13/09/14 16:56:56 GMT FROM: Chryssa Kouveliotou at MSFC Andrew C. Collazzi (NASA/ORAU), Shaolin Xiong (UAH), and Chryssa Kouveliotou (NASA/MSFC), report on behalf of the GBM-Magnetar Team: At 15:00:28.44 UT on 13 September 2013, the Fermi Gamma-Ray Burst Monitor triggered and located a very bright, SGR-like burst (trigger 400777231/130913625). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 278.88, Dec = -8.49 (J2000 degrees, equivalent to J2000 18h 35m, -8d 29'), with a statistical uncertainty of 1.0 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This burst consists of a single pulse, with a duration of T90 = 112 +/- 6 ms. The burst is well-fit by a two blackbody model with blackbody temperatures of kT1 = 5.3 +/- 0.2 keV and kT2 = 13.0 +/- 0.4 keV. The corresponding peak flux integrated over 4ms (8-200 keV) is (1.12 +/- 0.02)E-05 erg/s/cm^2. The fluence during T0-0.016s to T0+0.132s is (1.66 +/- 0.02)E-6 erg/cm^2. This interval is also well fit by a Comptonized model with Epeak = 32.4 +/- 0.6 and alpha = -0.40 +/- 0.09. This burst was followed by another, fainter, SGR-like trigger at 18:10:05.95 UT (trigger 400788608/130913757). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 281.25, Dec = -8.35 (J2000 degrees, equivalent to J2000 18h 35m, -8d 29'), with a statistical uncertainty of 7.6 degrees (see above on GBM location errors). The second burst comprises a single pulse with a duration of T90 = 72 +/- 25 ms. Its spectrum is best fit by a OTTB model with kT = 58.0 +/- 12.0 keV. The corresponding peak flux, integrated over 4ms (8-200 kev), is (6.2 +/- 0.7)E-07 erg/s/cm^2. The fluence during T0-0.032s to T0+0.080s is (6.9 +/- 0.81)E-8 erg/cm^2. Given the closeness of these bursts in location and in time, we suggest that they come from the same source, most likely SGR J1833-0832; however, we note that the 3-sigma contour for both bursts contains several known magnetar sources. The analysis results presented above are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15236 SUBJECT: INTEGRAL detection of a SGR-like burst likely from SGR J1745-29 DATE: 13/09/20 15:09:34 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, M.Tuerler (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: An off-line analysis of the IBAS WEAK Alert n. 6947 shows that this sub-threshold trigger (6.9 sigma) is due to a real event detected at 12:38:35.5 UT of September 20 in the IBIS/ISGRI data. Its refined coordinates (J2000) are: R.A.: 266.406 deg DEC.: -29.019 deg with an uncertainty of 2.6 arcmin (90% c.l.). The burst had a duration of about 30 ms, a soft spectrum and a fluence of about 2x10^-8 erg/cmq (20-100 keV). Its position is consistent with that of SGR J1745-29 (Rea et al. 2013, ATel n.5032) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15238 SUBJECT: Fermi Trigger 401326696: MASTER prompt optical observations DATE: 13/09/21 12:42:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs H. Levato and C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) C. Mallamaci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA) E. Gorbovskoy, V. Lipunov, V. Kornilov, D. Denisenko, A. Kuznetsov, D. Kuvshinov, A. Belinski, N. Tyurina, N. Shatskiy, P. Balanutsa, D. Zimnukhov, V.V. Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute A. Tlatov, A.V. Parhomenko, D. Dormidontov, V. Sennik Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, S. Yazev, N.M. Budnev, O. Gres, O. Chuvalaev, V.A. Poleshchuk Irkutsk State University V. Yurkov, Yu. Sergienko, D. Varda, E. Sinyakov Blagoveschensk Educational State University, Blagoveschensk V. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University MASTER-ICATE robotic very wide field cameras (FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec, http://observ.pereplet.ru) located in Argentina (Observatorio Astronomico Felix Aguilar, http://93.180.27.230:8080/) synchronously observed 35% part of FERMI GRB130919A (trigger 401326696) error box before, during and after the trigger. Since 40 sec after the trigger cameras pointed to FERMI alert our FOV cover 95% part of error box. We haven`t found optical transient within FERMI error-box our first (5 s exposure) set. The 5-sigma upper limit has been about 12.0 mag. The 5-sigma upper limit on coadd first 30 images is about 13.0 mag. The first seconds movie locate here http://master.sai.msu.ru/static/GRB130919A.gif Our cameras are continuously imaging the sky with 5 sec exposures. The more accurat error box (by IPN) is requied. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15245 SUBJECT: IPN Triangulation of SGR-like burst 130913 - probable association with SGR/AXP 1E1841-045 DATE: 13/09/24 19:05:37 GMT FROM: Valentin Pal'shin at Ioffe Inst V. Pal'shin, R. Aptekar, D. Frederiks, S. Golenetskii, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, K. Hurley on behalf of the IPN, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, on behalf of the Fermi GBM team, and S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, report: The bright SGR-like burst detected by Fermi-GBM at 15:00:28.44 UT on 13 September 2013 (Collazzi, Xiong, and Kouveliotou, GCN 15228) was also observed by Konus-Wind, INTEGRAL SPI-ACS, and Swift-BAT. The burst was outside the coded field of view of the BAT. We have triangulated it to an annulus centered at RA(2000)=304.668 deg (20h 18m 40s) Dec(2000)=+54.308 deg (+54d 18' 30"), whose radius is 62.790 ± 3.144 deg (3 sigma). The position of SGR 1833-0832 (the suggested source of two GBM SGR-like bursts: GCN 15228) lies outside the annulus, and therefore this SGR is unlikely to be the source of the bursts. The position of SGR/AXP 1E1841-045 (=PSR J1841-0456) lies 0.230 deg (0.2 sigma) from the annulus center line and 3.89 deg from the GBM position reported in GCN 15228 (and 4.08 deg from SGR 1833-0832). So it is likely that the bright SGR-like burst 130913 originated from this SGR/AXP. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/130913_T54028/IPN/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15277 SUBJECT: US Government shutdown may impact GRB operation of GCN DATE: 13/09/30 21:51:01 GMT FROM: Craig Markwardt at NASA/GSFC C. B. Markwardt (NASA/GSFC), S. D. Barthelmy (NASA/GSFC), N. Gehrels (NASA/GSFC), F. E. Marshall (NASA/GSFC) on behalf of GCN announce: A lapse in appropriations of the US Federal government may significantly impact the operation of the GCN. We are uncertain regarding the scope of the impact, but network access to NASA GSFC systems where GCN is hosted may be cut off from the general public. This may lead to the possibility of being unable to accept or distribute Notices and Circulars. The GCN web site (gcn.gsfc.nasa.gov) may also be unavailable. The impacts could start as early as 00:01 UT October 1. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15279 SUBJECT: Swift Operations in the event of a US Government shutdown DATE: 13/10/01 02:55:47 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea (PSU) on behalf of the Swift Science Operations Team As Swift's Mission Operations Center (MOC) is located at Penn State, rather than a NASA facility, it will remain fully staffed and operational in the event of a US Government shutdown. However, a shutdown may affect the visibility of NASA-based websites, such as the Swift Science Data Center (SDC) and the GCN, to the outside world (including the Swift MOC). If the SDC and GCN are down, our ability to report on accurate localization of burst afterglows and evolution of burst light-curves will likely be compromised. Also our partner SDC sites in the UK and Italy will likely not receive new Swift data if the NASA SDC is not available. If GCN becomes unavailable, we have put in place a backup webpage that hosts the first response GCN Circulars for new Swift bursts (i.e. those reporting the initial detection). It can be found at this URL: http://www.swift.psu.edu/gcn Since we cannot disseminate GCN Notices or Circulars if the GCN site goes off-line, interested parties are urged to check this site periodically during any US Government shutdown. Also, the Swift iPhone/iPad app, found here: https://itunes.apple.com/us/app/swift-explorer/id465669299?mt=8 can be used to be alerted when a new GRB is detected through push notifications. Swift's TOO website will remain online during any shutdown and our capability to perform TOO uploads is not expected to be affected during any shutdown. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15285 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 402405063 / 131002466 is not a GRB DATE: 13/10/02 14:41:52 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 402405063 / 131002466 at 11:11:00.52 UT on 02 October 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15289 SUBJECT: Swift J1242.9-3530, Swift-BAT refined analysis DATE: 13/10/02 18:43:17 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T0 to T+1699 sec from the recent telemetry downlink, we report further analysis of Swift J1242.9-3530 (formerly cited as GRB 130930A, BAT trigger #572489) (Ukwatta, et al., GCN Circ. 15276). The BAT ground- calculated position is RA, Dec = 190.725, -35.511, which is RA (J2000) 12h 42m 53.9s Dec (J2000) -35d 30' 40" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%. The mask-weighted light curve varies slowly over the duration of the observation. The emission appears to extend before and after the observation so we cannot determine a T90 interval. The time-averaged spectrum from T0 to T0+1699 sec is best fit by a simple power- law model. The power-law index of the time-averaged spectrum is 1.90 +- 0.18. The fluence in the 15-150 keV band is (3.9 +/- 0.4) x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.036 +- 0.004 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The source is also detected at a similar intensity in ground analysis of an earlier observation, from T0-46108 to T0-44561 seconds, but is not detected in an observation with a similar pointing from T0-51899 to T0-50201 seconds. The 90% confidence upper limit is 0.2 times the intensity observed later. We note that the location of the source is 27 degrees from the Galactic plane and not in the direction of the Galactic center. The narrow-field instruments of Swift cannot observe this location until late November at the earliest due to the proximity of the Sun. The data included in the automated analysis covers only T-239 to T+963 seconds. The results of the batgrbproduct automated analysis will be available if the US government ever returns to normal operations at http://gcn.gsfc.nasa.gov/notices_s/572489/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15323 SUBJECT: Trigger 574266 is not a Swift detection of a known source DATE: 13/10/11 22:55:55 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), A. Y. Lien (NASA/GSFC/ORAU), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 22:16:58 UT, the Swift Burst Alert Telescope (BAT) triggered on a rate increase (trigger=574266), and produced an image. This image included a statistically marginal peak which was 6 arcminutes from the RS CVn source VY Ari. Swift slewed immediately to the peak location. The BAT on-board calculated location is RA, Dec 42.286, +7.440 which is RA(J2000) = 02h 49m 09s Dec(J2000) = +07d 26 24 with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 30 sec, starting gradually at about T-20. The peak count rate was ~3386 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 22:18:47.5 UT, 109.3 seconds after the BAT trigger. No source was detected in 957 s of promptly downlinked data, which covered 84% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 113 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.22. When a marginal BAT image peak is found near to a previously-known source, Swift is programmed to make follow-up observations to test whether the detection is real. In this case, the strength of the rate variation in the BAT light curve is inconsistent with the low significance of the image peak location, and the peak location is outside of the expected BAT error circle for the VY Ari source. For these reasons, we believe that VY Ari is not the source of the BAT lightcurve variations, which may be due to a GRB outside of the BAT FOV. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15324 SUBJECT: Fermi403206457: iPTF detection of a possible optical afterglow DATE: 13/10/12 12:09:55 GMT FROM: Mansi M. Kasliwal at Caltech/Carnegie M. M. Kasliwal (Carnegie Observatories/Princeton), L. P. Singer (Caltech) and S. B. Cenko (NASA/GSFC) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: Starting 2013-10-12 05:26 UT, we imaged about 70 deg^2 in the vicinity of the localization of the Fermi-GBM trigger 403206457 with the Palomar 48-inch Oschin telescope (P48). Sifting through 10,816 candidate variable sources in the GBM error circle using standard iPTF vetting procedures including Palomar 60-inch follow-up, we identify iPTF13dsw as a possible optical afterglow candidate: RA(J2000) = 02h 10m 06.38s DEC(J2000) = -04d 24' 40.3" Light Curve: R=19.7mag @ 05:26 UT (P48), R=20.2mag @ 08:07 UT (P60) iPTF13dsw is 3.4 deg away from the center of the final GBM localization (68% statistical confidence radius of 2.75 deg). Nothing was detected at this location to a limiting magnitude of 20.6 mag on 2013 Sep 25. At 08:56 UT, we obtained a Gemini-South/GMOS spectrum in twilight. The spectrum is mostly featureless, with no prominent emission or absorption lines between 5100-9300A. Further observations are encouraged to determine the nature of the source and whether it is related to the Fermi trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15325 SUBJECT: Fermi403206457: NOT optical observations DATE: 13/10/13 05:21:49 GMT FROM: Dong Xu at DARK/NBI D. Xu, D. Malesani (DARK/NBI), T. Kruehler (ESO), J.P.U. Fynbo (DARK/NBI), P. Jakobsson (U. Iceland) and John Telting (NOT) report on behalf of a larger collaboration: We observed the location of the candidate optical afterglow (iPTF13dsw; Kasliwal et al., GCN 15324) of the Fermi-GBM trigger 403206457 with the NOT telescope equipped with ALFOSC. We obtained two R-band images with an exposure time of 300 s each starting at 01:32 UT 2013-10-13 in a good seeing of ~0.65". The candidate afterglow is clearly detected in each image as a point-like source, and we measure an R-band magnitude of R = 21.6 mag assuming R = 18.36 mag for the nearby star at RA = 02:10:07.95, Dec = -04:24:41.7 at a midpoint of 01:35 UT. Accounting for the different calibration system with respect to the magnitudes given in Kasliwal et al. (GCN 15324), the source has faded by approximately 1.6 magnitudes with respect to the earlier P60 measurement. Under the assumption that the transient decays as a single power-law, this fading corresponds to a decay index of ~1.6, not untypical of GRB afterglows at the given epoch. We thank S. B. Cenko for private information about the photometric calibration of the P60 measurement. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15326 SUBJECT: Fermi403206457: Weihai optical upper limit DATE: 13/10/13 05:42:47 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), C.-M. Zhang, C. Cao, S.-M. Hu (SDU) report: We observed the location of the candidate optical afterglow (iPTF13dsw; Kasliwal et al., GCN 15324) of the Fermi-GBM trigger 403206457 with the 1m telescope located in Weihai, Shandong, China. We obtained 5x600s R-band frames at a mean time of 2013-10-12 18:01:29 UT (i.e., 24.23 hr after the Fermi-GBM trigger) under some clouds. No optical source is detected at the iPTF location in the stacked image down to a limiting magnitude of R > ~20.0 mag, calibrated with the nearby SDSS field. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15327 SUBJECT: Fermi403206457: continued P60 observations and fading behavior DATE: 13/10/13 07:26:44 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech), S. B. Cenko (GSFC), and M. M. Kasliwal (Carnegie Observatories/Princeton) report: We imaged PTF13dsw, the possible optical counterpart to Fermi trigger 403206457 (Kasliwal et al., GCN 15324) with the Palomar 60-inch telescope starting at 05:16:19 UT in i, r, and g filters. Five exposures of 180 seconds each were acquired per filter. Calibrating to USNO B1.0 stars in the field, photometry of the candidate gives an approximate magnitude of R = 21.2 (+/- 0.2) in a stack of 15 minutes of r-band imaging at midpoint UT 05:40. As also noted by Malesani et al. (GCN 15325) the continued, significant fading relative to the previous night is consistent with that of a GRB afterglow and strengthens the association of this source with the Fermi trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15329 SUBJECT: Swift-XRT detection of iPTF 13dsw/Fermi403206457 DATE: 13/10/13 08:25:59 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 4.9 ks of XRT data for the candidate afterglow iPTF 13dsw (Kasliwal, Singer & Cenko, GCN Circ. 15324; Xu et al., GCN Circ. 15325; GCN Circ. 15326; Perley, Cenko & Kasliwal, GCN Circ. 15327; Sudilovsky, Tanga, & Greiner, GCN Circ. 15328), obtained on October 12, between 17:06 and 20:54 (starting approximately 24 hours after Fermi Trigger 403206457). A faint X-ray source consistent with the iPTF 13dsw position is detected: RA, Dec = 32.5255, -4.4117, which is equivalent to RA(J2000) = 02h 10m 06.11s Dec(J2000) = -04d 24' 42.1" with an uncertainty of 4.1 arcsec (radius, 90% confidence). Currently the source has a 0.3-10 keV count rate in the Swift-XRT of (5.9 +0.9/-0.8)e-3 count s^-1. We cannot determine at the present time whether the source is fading. Given the small number of detected X-ray photons, any spectral analysis is uncertain. However, the spectrum can be suitably approximated by a power-law with Gamma = 1.5 +0.6/-0.7, absorbed by the Galactic NH in this direction of 1.85e20 cm^-2. The observed (unabsorbed) flux is 2.9e-13 (3.0e-13) erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15330 SUBJECT: iPTF 13dsw/Fermi403206457: X-Shooter redshift DATE: 13/10/13 10:27:04 GMT FROM: Jochen Greiner at MPI A. Rau (MPE Garching), T. Kruehler (ESO), J. Greiner (MPE Garching) report for the GROND team: We observed the optical afterglow candidate iPTF13dsw of the Fermi-GBM trigger 403206457 (Kasliwal et al. 2013, GCN 15324; Xu et al. 2013, GCN 15325; Perley et al. 2013, GCN 15327; Sudilovsky et al. 2013, GCN 15328) using ESO/VLT UT3 equipped with the X-shooter spectrograph. The observations started on 2013-10-13 at 03:59 UT. A total exposure of 5x900 s was obtained, covering the spectral range from ~3000 AA to ~24000 AA. In the spectrum, we identify several very weak absorption features which we interpret as absorption from FeII, MgII and MgI at a common redshift of z = 1.874. This redshift is consistent with flux being detected down to ~3200 AA, and a broad absorption feature around 3400 AA corresponding to Lyman\alpha. The combined evidence of fading, powerlaw slope SED and redshift suggests iPTF13dsw to be the optical afterglow of GRB 131011A. We thank the Paranal staff for expert support, in particular Andrea Mehner, Christophe Martayan, Julio Navarrete, Felipe Gaete, L. Schmidtobreick, and A. Smette. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15345 SUBJECT: Fermi GBM data availability during U.S. government shutdown DATE: 13/10/16 20:12:14 GMT FROM: Valerie Connaughton at UAH/NSSTC Andreas von Kienlin (MPE) and Valerie Connaughton (UAH) report for the GBM team: Fermi GBM operations are proceeding during the U.S. government shutdown. GCN trigger notices and GRB positions are being distributed, and GRB Burst Advocates are processing and supplying positions for GRB triggers. GBM data products are usually supplied by the instrument team to the Fermi Science Support Center and hosted on the HEASARC servers at NASA Goddard Space Flight Center. These servers are offline during the U.S. government shutdown with the consequence that GBM data files have not been available. Data servers at GBM partner Max Planck Institute in Garching, Germany, have now been deployed to host GBM GRB trigger data until NASA GSFC resumes normal operations. GRB trigger data from October 1 2013 onwards are available for download at: http://www2011.mpe.mpg.de/gbm/ Procedures to supply these data products require human intervention and are thus subject to delays outside CET working hours. Please direct any inquiries to valerie@nasa.gov. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15377 SUBJECT: Fermi GBM trigger 13121024.436 is not a GRB DATE: 13/10/25 08:52:17 GMT FROM: Suzanne Foley at MPE S. Foley (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 404303265 (13121024.436) at 10:27:42.30 UT on 24 October 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15384 SUBJECT: Swift Trigger 575905: a possible GRB DATE: 13/10/26 07:03:54 GMT FROM: David Palmer at LANL S. B. Cenko (GSFC), S. T. Holland (STScI), L. Izzo (URoma/ICRA), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 06:39:32 UT, the Swift Burst Alert Telescope (BAT) and located a possible GRB in an image trigger (trigger=575905). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 15.547, +32.487 which is RA(J2000) = 01h 02m 11s Dec(J2000) = +32d 29' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, there is no obvious variation in the BAT lightcurve. The XRT began observing the field at 06:41:33.9 UT, 121.1 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 127 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07. Because the BAT image peak is of marginal significance (7.06 sigma) and because there is only 2.5 seconds of XRT data immediately available, which does not show a counterpart, we cannot yet confirm or deny the reality of this possible GRB. A final determination of the nature of this trigger will require the full set of downlinked data. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15386 SUBJECT: Swift Trigger 575905: KAIT Optical Upper Limit DATE: 13/10/26 07:37:56 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng, Alexei V. Filippenko, Adam Morgan (UC Berkeley), and S. B. Cenko (NASA/Goddard Space Flight Center) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift Trigger 575905 (Cenko et al., GCN 15384) starting at 06:42:00 UT, 148 s after the burst. Observations were performed with an automatic sequence in the V, I, and clear(roughly R) filters, and the exposure time was 20 s per image. Comparing to the SDSS image, we do not detect new sources within BAT error circle. Typical limiting magnitudes of our single clear image is about 18.7. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15387 SUBJECT: Swift Trigger 575905: ROTSE-III Optical Limits DATE: 13/10/26 08:01:52 GMT FROM: Farley V. Ferrante at Southern Methodist U/ROTSE F. V. Ferrante, G. Dhungana, and R. Kehoe (SMU) report on behalf of the ROTSE GRB team: The 0.45-m ROTSE-IIIb, located at McDonald Observatory, Texas, responded to Swift trigger 575905 (Cenko et al., GCN 15384), producing images beginning 7.7 s after the GCN notice time. An automated response took the first image at 06:40:53.8 UT, 81.0 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 60 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0. Imaging is on going. Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma Swift/BAT error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 13.3-16.9; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 06:40:53.8 06:42:40.9 107 16.4 81.0 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15393 SUBJECT: Swift-BAT Trigger 575905 is probably not a real source DATE: 13/10/28 17:34:05 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings and Valerio D'Elia on behalf of the Swift science team Swift-BAT trigger 575905 (Cenko et al., GCN 15384) is probably due to a fluctuation in the image domain, not to any astrophysical source. While the BAT significance level (7.0 sigma) usually is high enough to indicate a real source, in this case the peak in the image is not robust with respect to very slight changes in parameters. The total XRT exposure for this field is 15ks. The source number 2 reported in Izzo et al. (GCN 15388), that was uncatalogued but below the RASS limit, has a bright star as optical counterpart. We thus conclude that source 2 is not related to the BAT emission, and that the slight variability observed for this object in the X-ray band is due to normal stellar activity. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15498 SUBJECT: Fermi GBM trigger 406351590 / 131117143 is not a GRB DATE: 13/11/17 19:24:46 GMT FROM: Veronique Pelassa at UAH V. Pelassa and S. Xiong (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: The Fermi Gamma-ray Burst Monitor (GBM) trigger 406351590 / 131117143 at 03:26:27.98 UT on 17 November 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15504 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 406601061 / 131120031 is not a GRB DATE: 13/11/20 02:50:21 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: The Fermi Gamma-ray Burst Monitor (GBM) trigger 406601061 / 131120031 at 00:44:18.02 UT on 20 November 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15524 SUBJECT: Fermi407254341: iPTF optical afterglow candidates DATE: 13/11/28 07:49:40 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech) and M. M. Kasliwal (Carnegie Observatories/Princeton) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: We imaged about 60 deg^2 in the vicinity of the localization of the Fermi-GBM trigger Fermi407254341 with the Palomar 48-inch Oschin telescope (P48), starting at 2013-11-28 03:40 UT (13.5 hours after the Fermi trigger). Sifting through 17,353 candidate variable sources in the GBM error circle using standard iPTF vetting procedures, we find the following optical afterglow candidates: iPTF13ecv, possibly fading, at R=18.6mag and with no coincident source visible in SDSS or in our reference images, at the coordinates: RA(J2000) = 20h 31m 47.76s Dec(J2000) = +00d 59' 23.4" iPTF13ect, at R=17.9 and near the core of a z=0.025 galaxy, at the coordinates: RA(J2000) = 20h 46m 44.63s Dec(J2000) = -01d 22' 07.8" iPTF13ecu, at R=19.1 and near the core of a z=0.030 galaxy, at the coordinates: RA(J2000) = 20h 40m 11.04s Dec(J2000) = -01d 37' 09.2" A diagram of the locations of these candidates and the nine P48 fields that we imaged in relation to the Fermi-GBM statistical+systematic error contours can be found at . We have submitted a Swift ToO request to follow up iPTF13ecv. We caution that many transient or variable sources are found in any such wide-area targeted search, and that at this burst's galactic latitude of -20 deg many foreground sources are likely. Further observations are encouraged to determine the nature of these sources, and whether one of them is related to the Fermi trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15582 SUBJECT: Swift Trigger 580319 is not a GRB DATE: 13/12/05 18:24:15 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), H. A. Krimm (CRESST/GSFC/USRA) and D. M. Palmer (LANL) report on behalf of the Swift Team: The Swift-BAT trigger 580319 (at 17:58:20 UT) is not due to an astrophysical event. This peak is due to a source that was misidentified as a result of a known race condition in the onboard software. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15593 SUBJECT: INTEGRAL Weak trigger #6403: AROMA-N Optical Observation DATE: 13/12/12 13:48:59 GMT FROM: Takanori Sakamoto at AGU D. Kawamura, T. Sakamoto, I. Takahashi, S. Sugai, A. Yoshida (AGU) We observed the field of INTEGRAL Weak trigger #6403 with the 12-inch AGU Robotic Optical Monitor for Astrophysical object - Narrow (AROMA-N) located at the Sagamihara campus of Aoyama Gakuin University. 60 images of 10 sec exposures and 30 images of 60 sec exposures were taken in the R filter starting from December 13 10:45:22 (UT) about 109 sec after the trigger (103 sec after the INTEGRAL weak trigger notice) and stopped on December 13 11:40:24 (UT). We do not detect the optical afterglow both in the individual images and the stacked image, which combined 89 good quality images, inside the INTEGRAL weak position. The estimated five sigma upper limit of the combined image (total exposure of 2390 sec) is ~17.0 mag using the USNO-B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15596 SUBJECT: Trigger 581129: Swift-BAT triggered on noise DATE: 13/12/15 03:46:03 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), D. Grupe (PSU), S. T. Holland (STScI), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), M. H. Siegel (PSU), M. C. Stroh (PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 03:26:43 UT, the Swift Burst Alert Telescope (BAT) triggered (581129). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 178.342, +47.942, which is RA(J2000) = 11h 53m 22s Dec(J2000) = +47d 56' 32" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single very weak peak structure with a duration of about 0.1 sec. The peak count rate was ~700 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 03:28:03.5 UT, 80.5 seconds after the BAT trigger. No source was detected in 604 s of promptly downlinked data, which covered 96% of the BAT error circle. UVOT took a finding chart exposure of 150 seconds with the White filter starting 83 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Due to the low significance in the BAT image and the lack of a detection in XRT and UVOT, we believe this trigger to be a noise event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15604 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 409187680/131219968 is not a GRB DATE: 13/12/20 00:56:49 GMT FROM: Binbin Zhang at UAH Bin-Bin Zhang (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 409187680 / 131219968 at 23:14:37.68 UT on 19 December 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15679 SUBJECT: Swift-BAT trigger 582894 is HD 1099 (Flare star) DATE: 14/01/04 18:18:00 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) on behalf of the Swift team reports: The Swift-BAT trigger 582894 was caused by a known flare star HR 1099, and is not due to a GRB. It was a 28-min image trigger. There was no immediate slew because of Earth limb constraint. At T+48 min, Swift did slew and XRT detected HR 1099. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15686 SUBJECT: Fermi410578384: iPTF optical afterglow candidates for a possible short GRB DATE: 14/01/05 16:37:28 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), M. M. Kasliwal (Carnegie Observatories/Princeton) and S. B. Cenko (NASA/GSFC) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: At 2014-01-05 01:33:01, Fermi GBM and INTEGRAL SPI-ACS triggered on a possible short event (Fermi trigger 410578384). From 7.4 to 10.5 hours after the burst, we imaged 74 deg^2 with the Palomar 48-inch Oschin telescope (P48), covering some of the intersection between the Fermi 1-sigma statistical+systematic error region and the IPN 3-sigma annulus. Sifting through 60,191 candidate variable sources using standard iPTF vetting procedures, we find the following optical afterglow candidates: iPTF14x, at R=19.7 mag, possibly fading, and near the galaxy SDSS J140427.10+485556.9, at the coordinates: RA(J2000) = 14h 04m 27.27s (211.113610 deg) Dec(J2000) = +48d 55' 55.3" (+48.932017 deg) iPTF14ac, at R=20.1 mag, near the galaxy SDSS J142230.44+482916.8 and in an apparent galaxy cluster at z=0.07, at the coordinates: RA(J2000) = 14h 22m 30.60s (215.627501 deg) Dec(J2000) = +48d 29' 21.5" (+48.489310 deg) iPTF14ae, at R=20.1 mag, possibly fading, near the source SDSS J134527.33+532615.3 (which SDSS classifies as a galaxy), at the coordinates: RA(J2000) = 13h 45m 27.34s (206.363914 deg) Dec(J2000) = +53d 26' 16.9" (+53.438029 deg) iPTF14ai, at R=20.6 mag, coincident with no obvious source in our reference images or in SDSS, at the coordinates: RA(J2000) = 13h 57m 46.05s (209.441870 deg) Dec(J2000) = +45d 16' 09.3" (+45.269258 deg) A diagram of the locations of these candidates, the Fermi-GBM and IPN localizations, and the ten P48 fields that we imaged can be found at . We caution that many contaminating transient or variable sources are found in any such wide-area targeted search, and that it is possible that none of our candidates are associated with the short GRB. Further observations are encouraged to determine the nature of these sources, and whether one of them is related to the Fermi and INTEGRAL trigger. We thank the Fermi and IPN teams for supplying us with the localizations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15695 SUBJECT: Swift-BAT triggered on KS 1947+300 DATE: 14/01/07 00:06:19 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. M. Chester (PSU), V. D'Elia (ASDC), D. Malesani (DARK/NBI), B. Sbarufatti (INAF-OAB/PSU) and B.-B. Zhang (UAH) report on behalf of the Swift Team: At 23:21:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located KS_1947+300 (trigger=583105). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 297.350, +30.231 which is RA(J2000) = 19h 49m 24s Dec(J2000) = +30d 13' 52" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is a very low significance image trigger. The XRT began observing the field at 23:36:42.6 UT, 934.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright X-ray source located at RA, Dec 297.39826, 30.20855 which is equivalent to: RA(J2000) = 19h 49m 35.58s Dec(J2000) = +30d 12' 30.8" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 170 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.5 arcseconds from that of known X-ray source KS 1947+300. No event data are yet available to determine the column density using X-ray spectroscopy. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 8.90 x 10^21 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 5.46e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of nominal 150 seconds with the White filter starting 942 seconds after the BAT trigger. The initial images are consistent with the identification of the source as KS 1947+300. Because of the density of catalogued stars and the large but uncertain extinction in the direction of the source, further analysis is required to report photometric measurements. The GCN notices were the result of a known race condition in the BAT on-board software causing a misidentification of the source. The ground processing correctly identified the source as KS 1947+300, which is currently in outburst (Kawagoe et al., ATEL #5438) and is continually seen by BAT (see http://swift.gsfc.nasa.gov/results/transients/weak/KS1947p300/ for the current light curve). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15698 SUBJECT: New Fermi-LAT GRB Table DATE: 14/01/07 22:40:47 GMT FROM: Daniel Kocevski at SLAC Daniel Kocevski (NASA/GSFC) and Giacomo Vianello (Stanford Univ.) report on behalf of the Fermi-LAT team: The Fermi-LAT collaboration would like to announce a new publicly available table hosted at NASA's Goddard Space Flight Center that summarizes Fermi observations of LAT detected GRBs. This table will feature preliminary LAT analysis, including pointing information, detection significance, and best known localization. The results presented in the table will be updated via the LAT burst advocates and should be available within 8-12 hours of the burst trigger, depending on the availability of the data. Please note that the results presented on the public Fermi-LAT GRB table are intended to be a quicklook guide to summarize LAT detections of GRBs which triggered Fermi-GBM, Swift, or other spacecrafts. The results presented in the table should therefore be considered preliminary and are superseded by results presented in any past or future Fermi-LAT collaboration publications and catalogs. The public Fermi-LAT GRB table can be found here: http://fermi.gsfc.nasa.gov/ssc/observations/types/grbs/lat_grbs/ The NASA point of contact for the table is Daniel Kocevski (daniel.kocevski at nasa.gov). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15731 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 411362827 is not a GRB DATE: 14/01/14 17:20:44 GMT FROM: Gerard Fitzpatrick at UCD G. Fitzpatrick (UCD), reports on behalf of the Fermi Gamma-ray Burst Monitor Team: The Fermi Gamma-ray Burst Monitor (GBM) trigger 411362827 (140114.144) at 03:27:04.44 UT on 14th of January 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15749 SUBJECT: Swift Trigger 584155 is MAXI J1421-613 DATE: 14/01/18 08:59:28 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. Pagani (U Leicester), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 08:39:19 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=584155) and located an outburst from a recently discovered transient, MAXI J1421-613 (Morooka et al., ATel #5750). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 215.411, -61.608 which is RA(J2000) = 14h 21m 39s Dec(J2000) = -61d 36' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 10 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~7 sec after the trigger. The XRT began observing the field at 08:40:43.9 UT, 84.2 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 215.4049, -61.6073 which is equivalent to: RA(J2000) = 14h 21m 37.17s Dec(J2000) = -61d 36' 26.1" with an uncertainty of 2.4 arcseconds (radius, 90% containment). This location is 10 arcseconds from the BAT onboard position, within the BAT error circle and consistent with the position of the MAXI J1421-613 transient. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.71 x 10^22 cm^-2, Kalberla et al. 2005), with an excess column of 2 (+2.01/-1.51) x 10^22 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 88 seconds after the BAT trigger. No credible optical counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15755 SUBJECT: Correction: MAXI J1421-613: Skynet PROMPT/R-COP observations DATE: 14/01/20 15:56:15 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, D. Reichart, A. Verveer, T. Spuck, A. LaCluyze, J. Haislip, A. Foster, N. Frank, K. Ivarsen, J. Moore, M. Nysewander, R. Beauchemin, T. Berger, M. Carroll, H. T. Cromartie, R. Egger, M. Hinckle, A. Ireland, M. Maples, L. Scott, and J. A. Crain report: In GCN 15753 (Trotter et al.), we mistakenly conflated the transient source MAXI J1421-613 (Baumgartner et al., GCN 15749, Swift trigger 584155) with GRB 140118 (Krim et al., GCN 15748, Lien et al., GCN 15750, Swift trigger 584136). We regret the error, and thank our colleagues who pointed it out. A corrected version of our observing report follows: Skynet observed the Swift-XRT localization of transient source MAXI J1421-613 (Baumgartner et al., GCN 15749, Swift trigger 584155) with one 24" and four 14" telescopes of the PROMPT array at Cerro Tololo, Chile, with two 14" telescopes of the PROMPT array at Siding Spring, Australia, and with the 14" R-COP telescope at Perth Observatory, Australia. Observations began 86s after the trigger, simultaneously in the BVRI bands. We detect no uncatalogued optical source in the Swift-XRT error circle. In stacks of exposures, we obtain the following upper limits: Mean Time Band Limit 10.8m I >19.6 14.9m R >19.1 11.7m V >19.8 14.9m B >19.1 6.94h I >17.3 7.10h R >16.9 6.02h V >20.4 6.04h B >20.4 Photometry is calibrated to five APASS-DR7 stars in the field, and has not been corrected for the extremely significant Galactic foreground extinction corresponding to E(B-V)=10.5 (Schlegel et al. 1998). No further Skynet observations are scheduled. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15758 SUBJECT: Fermi412093190: iPTF optical counterpart search DATE: 14/01/23 10:04:44 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), M. M. Kasliwal (Carnegie Observatories/Princeton), S. B. Cenko (NASA/GSFC), and Y. Cao (Caltech) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: We have searched for optical counterparts of Fermi GBM trigger 412093190 (2014-01-22 14:19:47.78) using the Palomar 48-inch Oschin telescope (P48). Starting at 11.97 hours after the Fermi trigger, we imaged an area of 75 deg^2 within the GBM 1-sigma statistical+systematic region, with a 34% chance of containing the true, unknown location of the source. We sifted through 14,681 candidate variable sources using standard iPTF vetting procedures. After obtaining spectra with the Palomar 200 inch (P200) for the most promising sources, no compelling optical afterglow candidates survived. We note the following unrelated optical transients: iPTF14ig, at R=19.9 +/- 0.1 mag, classified as a SN Ia based on P200 observations, at the coordinates: RA(J2000) = 03h 32m 23.94s ( 53.099768 deg) Dec(J2000) = +10d 07' 06.2" (+10.118386 deg) iPTF14ih, at R=20.2 +/- 0.2 mag, classified as a SN II based on P200 observations, on the outskirts of the galaxy 2MASX J03394459+1548035 a.k.a. PGC 1493639, at the coordinates: RA(J2000) = 03h 39m 43.88s ( 54.932815 deg) Dec(J2000) = +15d 47' 43.4" (+15.795391 deg) iPTF14ip, at R = 19.6 +/- 0.1 mag, on the edge of the galaxy SDSS J034353.55+094512.9, at the coordinates: RA(J2000) = 03h 43m 53.69s ( 55.973710 deg) Dec(J2000) = +09d 45' 13.1" (+09.753634 deg) Given the nearby galaxy and lack of recent limits, we consider it likely iPTF14ip is also an unrelated foreground supernova. We will attempt future observations to confirm its origin. A diagram of the locations of these candidates, the Fermi-GBM localization, and the ten P48 fields that we imaged can be found at . We thank Andrew Drake for promptly obtaining the P200 spectra. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15823 SUBJECT: Trigger 586482: Swift detection of GROJ1744-28 DATE: 14/02/12 17:49:22 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), S. T. Holland (STScI) and J. A. Kennea (PSU) report on behalf of the Swift Team: At 17:36:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located GROJ1744-28 (trigger=586482). Swift was already on this source from the previous trigger. The BAT on-board calculated location is RA, Dec 266.107, -28.743, which is RA(J2000) = 17h 44m 26s Dec(J2000) = -28d 44' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED-shaped pulse with a duration of about 15 sec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 17:36:35.0 UT, 27.0 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 266.1382, -28.7407 which is equivalent to: RA(J2000) = +17h 44m 33.17s Dec(J2000) = -28d 44' 26.5" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 98 arcseconds from the BAT onboard position, within the BAT error circle. This position is 1.0 arcseconds from GRO J1744-28. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.92e-09 erg cm^-2 s^-1 (0.2-10 keV). This is the 3rd BAT trigger on GRO J1744-28 in the past 24 hours, the first was reported by Linares et al. (ATEL #5883). The 2nd trigger occurred 17:15:32UT (trigger=586480), which was an image trigger and it is not clear if that trigger was caused by a burst or simply the brightness of the persistent flux. The current trigger is a rate trigger and was caused by a flare. The source is showing rapid bursting activity currently. BAT has triggered on GRO J1744 two previous times since the latest outburst began, on 2014 January 19 20:11UT and 2014 January 23 09:00UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15860 SUBJECT: Fermi GBM trigger 140214230 is not a GRB DATE: 14/02/18 18:30:37 GMT FROM: Hoi-Fung Yu at MPE Subject: Fermi GBM trigger 140214230 is not a GRB Hoi-Fung Yu (MPE) reports on behalf of the Fermi GBM Team: "The recent Fermi GBM trigger 414048665 / 140214230 at 05:31:02.74 UT on 14 February 2014, tentatively classified as GRB, is in fact due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15863 SUBJECT: Swift follow-up of an Integral weak transient DATE: 14/02/20 11:48:31 GMT FROM: Rhaana Starling at U of Leicester R. Starling (U. Leicester) reports: We observed the position of the Integral weak transient #6467 with Swift on 19th February 2014 starting at 18:37 UT, 2.5 hours after the Integral trigger. We do not detect any source in the XRT field of view in a 2.98 ks observation. The 3-sigma upper limit on the 0.3-10 keV count rate at the Integral position (RA, Dec: 204.097, -45.0619 deg) is 0.003 count/s. We thank the Swift team for carrying out this rapid ToO. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15883 SUBJECT: iPTF14yb: iPTF Discovery of an Optical Afterglow-like Transient DATE: 14/02/26 21:40:35 GMT FROM: S. Bradley Cenko at NASA/GSFC S. B. Cenko (NASA/GSFC), M. M. Kasliwal (OCIW/Princeton), D. A. Perley (Caltech), D. Jewitt (UCLA), A. V. Filippenko (UC Berkeley), A. Horesh (Weizmann Institute), A. De Cia (Weizmann Institute), A. Rubin (Weizmann Institute), A. Gal-Yam (Weizmann Institute), O. Yaron (Weizmann Institute), I. Arcavi (LCOGT/KITP), Y. Cao (Caltech), and P. E. Nugent (LBNL/UCB) report on behalf of a larger collaboration: As part of the ongoing Intermediate Palomar Transient Factory survey, we report the discovery of a new optical transient source, iPTF14yb, located at RA = 14:45:58.01, Dec: +14:59:35.4 (J2000.0). In an image obtained at the Palomar 48-inch Oschin Schmidt telescope beginning at 10:18 UT on 2014 February 26, we measure an r-band magnitude of r = 18.42 +/- 0.05 mag. In subsequent P48 imaging, the source faded rapidly, with a measured magnitude of r = 20.4 +/- 0.2 mag at 13:08 UT on 2014 February 26. Nothing was detected at this location (r > 20.5 mag) in an image obtained at 09:05 UT on 2014 February 26 (i.e., 1.2 hours prior to discovery). A coaddition of previous (i)PTF imaging of this location from 2009-2012 with P48 reveals no sources at this location to a limit of r > 22.7 mag. We obtained a target-of-opportunity spectrum with the Low Resolution Imaging Spectrometer (LRIS) mounted on the 10 m Keck 1 telescope beginning at 15:27 UT on 2014 February 26 (i.e., 5.2 hours after discovery). Our spectrum covers the wavelength range from the atmospheric cutoff at ~ 3200 A to 10000 A. Super-imposed on a relatively flat continuum, we detect a number of absorption features at a common redshift of z = 1.98 (preliminary wavelength calibration), including Mg II, Fe II, Mg I, and Ly-alpha. Given the rapid temporal evolution, the large distance and luminosity, and the observed spectrum, iPTF14yb resembles the optical afterglow of a gamma-ray burst. We have triggered radio and X-ray observations to confirm this hypothesis, and encourage additional follow-up at all wavelengths (including archival searches of this location). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15884 SUBJECT: iPTF14yb: Swift-XRT detection DATE: 14/02/27 09:26:21 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore, P.A. Evans and K.L. Page (U. Leicester) report on behalf of the Swift-XRT team: We have analysed 2.3 ks of XRT data for the PTF-detected transient / possible GRB iPTF14yb, from 24.8 ks to 42.8 ks after the time of the initial PTF observation. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the PTF error circle. The refined XRT position is RA, Dec = 221.49179, +14.99396 which is equivalent to: RA (J2000): 14 45 58.03 Dec(J2000): +14 59 38.3 with an uncertainty of 3.7 arcsec (radius, 90% confidence). This position is 2.9 arcsec from the PTF position. The source has a mean count rate of 4.7e-02 ct/sec and shows marginal evidence for fading at the 1.6-sigma level, with a decay slope of 1.14, however more data are required to confirm this. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.15 (+0.51, -0.30). The best-fitting absorption column is consistent with the Galactic value of 1.5 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (3.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 1.5 x 10^20 cm^-2 Intrinsic column: 0 (+6.2, -0) x 10^21 cm^-2 at z=1.98 Photon index: 2.15 (+0.51, -0.30) The ROSAT (PSPC) All Sky Survey 3-sigma upper limit at the position of this source is 0.056 ct/sec, which, given the spectrum above, corresponds to 0.03 ct/sec in the XRT; hence the source was not seen at the current flux level at the time of the RASS. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00033157. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15886 SUBJECT: iPTF14yb: RATIR Optical and NIR Observations of the optical transient DATE: 14/02/27 19:18:21 GMT FROM: Antonino Cucchiara at NASA/GSFC Antonino Cucchiara (ORAU/GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of the transient iPTF14yb (Cenko et al., GCN 15883, Beardmore et al., GCN 15884) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2014/02 27.28 to 2014/02 27.54 UTC (20.53 to 26.68 hours after the reported time of discovery), obtaining a total of 3.91 hours exposure in the r and i bands and 1.64 hours exposure in the Z, Y, J, and H bands. For the source reported by Cenko et al. (GCN 15883), in comparison with the SDSS DR9 and 2MASS, we obtain the following detections and upper limit (3-sigma): r 22.28 +/- 0.09 i 22.02 +/- 0.09 Z 21.98 +/- 0.24 Y 22.12 +/- 0.35 J 21.88 +/- 0.35 H > 21.59 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the transient. Our photometry indicates that the transient is fading in r band according to a single power law with temporal index alpha=1.04. This behavior is also typical of a long gamma-ray burst type transient as suggested by Cenko et al. (GCN 15883) We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15887 SUBJECT: PTF14yb: GROND Transient Detection DATE: 14/02/27 22:00:43 GMT FROM: John Graham at STScI K. Varela, J. F. Graham, J. Greiner, (all MPE Garching) and D. A. Kann (TLS Tautenburg) report on behalf of the GROND team: We observed the iPTF-detected GRB optical afterglow-like transient iPTF14yb (Cenko et al. GCN 15883) simultaneously in g'r'i'z'JHK with the GROND instrument (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at La Silla Observatory (Chile). Observations started at 08:09 UT on February 27th 2014 (approximately 22 hours after initial detection). We clearly detect the source in the g'r'i'z' bands at the following (AB) magnitudes and errors: g = 22.37 +/- 0.04 r = 22.11 +/- 0.03 i = 22.07 +/- 0.06 z = 22.11 +/- 0.03 We do not detect the source in the JHK bands above our 3-sigma AB limits given below: J > 21.6 H > 21.0 K > 19.7 The values we measure are comparable with the concurrent RATIR observations (Cucchiara et al., GCN 15886). Given magnitudes are calibrated against SDSS field stars (g'r'i'z') as well as 2MASS field stars (JHK) and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998). Given the unusually flat spectral slope of 0.25 +/- 0.07 (after correcting for Galactic extinction) apparent in our photometry and the flat spectra noted in Cenko et al. (GCN 15883) with the present data we cannot distinguish between a powerlaw or a thermal spectrum. Deep NIR imaging is encouraged to allow this distinction. John Graham //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15919 SUBJECT: iPTF14yb: JVLA and CARMA observations DATE: 14/03/04 21:28:11 GMT FROM: Assaf Horesh at Caltech A. Horesh (Weizmann Institute), A. Corsi (GWU), D. Perley (Caltech), B. Cenko (NASA/GSFC), and A. Rubin (Weizmann Institute) report on behalf of a larger collaboration: We observed the transient iPTF14yb (Cenko et al.; GCN 15883; ATel #5924) with the JVLA and CARMA. The JVLA observations were undertaken on 2014 Feb 27.7 UT at center frequencies of 6 GHz (C band) and 22 GHz (K band). The JVLA observations resulted in a null-detection with 3-sigma upper limits of 45 microJy and 153 microJy in the C- and K-bands, respectively. The CARMA observation was carried out on 2014 Feb 28.5 UT at a center frequency of 95 GHz. We report a 3-sigma upper limit of 0.75 mJy. We thank the CARMA and the JVLA staff for scheduling this target of opportunity. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15933 SUBJECT: Trigger 590503: Swift-BAT triggered on noise DATE: 14/03/05 23:38:37 GMT FROM: Mike Siegel at PSU/Swift MOC W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), C. B. Markwardt (NASA/GSFC), A. Maselli (INAF-IASFPA), T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 23:18:37 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=590503). Swift slewed immediately to the burst location. The BAT light curve showed a strongly rising background level as Swift entered the SAA. Combined with the low significance image trigger (5.81 sigma), we conclude that this trigger was caused by noise while entering the SAA. The XRT began observing the field at 23:20:52.7 UT, 135.7 seconds after the BAT trigger. The only source detected is significantly outside the BAT error circle and has the morphology of a cosmic ray. This is therefore unlikely to be a real detection. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15967 SUBJECT: GRO J1744-28: Fermi GBM observation DATE: 14/03/12 16:49:47 GMT FROM: Hoi-Fung Yu at MPE Subject: GRO J1744-28: Fermi GBM observation Hoi-Fung Yu (MPE) reports on behalf of the Fermi GBM Team: "At 03:46:41.88 UT on 12 March 2014, the Fermi Gamma-Ray Burst Monitor triggered on a burst from the bursting pulsar GRO J1744-28 (trigger 416288804 / 140312157), which was also detected by Swift (Kennea et al. 2014, ATel #5845). A second burst triggered GBM at 06:55:18.28 UT. Both triggers were classified as unreliable sources by the FSW, but were indeed due to GRO J1744-28. The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight for both triggers is 58 degrees. The GBM light curve of both triggers show a single pulse with a duration of about 10 s (8-300 keV). For the first trigger, the time-averaged spectrum from T0-3.712 s to T0+6.528 s is adequately fit by a simple power law function with index -5.3 +/- 0.1. For the second trigger, the time-averaged spectrum from T0-6.432 s to T0+5.856 s is adequately fit by a blackbody with kT 4.04 +/- 0.08 keV. The spectral analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15971 SUBJECT: Fermi416242156: possible iPTF counterpart DATE: 14/03/12 18:50:02 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), S. B. Cenko (NASA/GSFC), and M. M. Kasliwal (Carnegie Observatories/Princeton) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: We have searched for optical counterparts of Fermi GBM trigger 416242156 (2014-03-11 14:49:13.10) using the Palomar 48-inch Oschin telescope (P48). We observed 10 fields, covering 73.0 deg2 and most of the Fermi GBM 1-sigma contour. We estimate a 54% chance that our fields contain the location of the source. Sifting through candidate variable sources using image subtraction and standard iPTF vetting procedures including photometry with the robotic Palomar 60" telescope (P60), we detect the candidate optical transient iPTF14aak, the coordinates: RA(J2000) = 11h 33m 14.47s (173.310295 deg) Dec(J2000) = +62d 05' 10.7" (+62.086313 deg) In our P48 image taken dt=0.51 days after the Fermi trigger, we measure r = 19.7 +/- 0.1 mag. In our P60 image taken dt=0.82 days after the trigger, we find a limit of r > 20.10 mag. Given a bright star about 1.3' to the west, it is possible that the P48 detection is a ghost. If not, then the P60 non-detection is evidence of fading with a power law of at least alpha~0.8. We have submitted a Swift target of opportunity to search for an X-ray counterpart of iPTF14aak. Further observations are encouraged to confirm the nature of the source, and determine if it is associated with the Fermi trigger. The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi416242156.pdf shows the ten P48 fields and the position of iPTF14aak in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16002 SUBJECT: Swift Trigger 592558 is not an astrophysical source DATE: 14/03/20 06:43:54 GMT FROM: David Palmer at LANL C. J. Mountford (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 06:11:00 UT, the Swift Burst Alert Telescope (BAT) found a marginal-significance peak (5.83 sigma) in a non-rate-triggered 64 second image (trigger=592558). Because the peak location was close (8.5 arcminutes) to a nearby galaxy, Swift slewed immediately to the location to make a confirmation observation with the narrow-field instruments. The BAT on-board calculated location is RA, Dec 190.636, +11.579 which is RA(J2000) = 12h 42m 33s Dec(J2000) = +11d 34' 44" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows no obvious count rate variation. The XRT began observing the field at 06:13:02.6 UT, 122.5 seconds after the BAT trigger. No source was detected in 1.2 ks of promptly downlinked data, which covered 97% of the BAT error circle. Given the sub-threshold nature of the trigger, the lack of features in the BAT light-curve and the fact that no X-ray source is detected, we believe this was just a noise event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16038 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 417486540 / 140326020 is not a GRB DATE: 14/03/26 16:21:35 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH), reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 417486540 / 140326020 at 00:28:57.95 UT on 26 March 2013, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16041 SUBJECT: Swift trigger 593744: detection of a flare from UV Cet DATE: 14/03/29 18:54:29 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 15:18:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located a peak consistent with the flare star UV Cet (trigger=593744). Swift could not slew to the location due to the Sun constraint. The BAT on-board calculated location is RA, Dec 24.764, -17.961, which is RA(J2000) = 01h 39m 03s Dec(J2000) = -17d 57' 40" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed no obvious activity, as is typical for a 64 second image trigger. Because of the Sun constraint, Swift will not be able to observe this source with the XRT and UVOT at this time. Although the image peak was of marginal significance (6.28 sigma) the close proximity to the known source location (0.013 degrees) and its status as a flare star make it highly likely that this is a real astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16044 SUBJECT: MAXI ID=745548350 is UV Ceti DATE: 14/03/30 12:49:37 GMT FROM: Takanori Sakamoto at AGU T. Sakamoto (AGU), M. Serino (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, R. Usui, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, Y. Nakano, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, M. Sasaki (Osaka U.), H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, M. Higa (Chuo U.), M. Yamauchi, K. Yoshidome, Y. Ogawa, H. Yamada (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: The MAXI Unknown Source Position Notice (EVENT_ID_NUM = 745548350) issued at 10:56:31 UT was the trigger from a known source, UV Ceti. We also want to note that the correct EVENT_ID_NUM of this event is 6745548350 not 745548350. We want to apologize for the confusion this might have caused. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16068 SUBJECT: Swift trigger 594286: Is likely a noise trigger DATE: 14/04/01 18:52:38 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), S. T. Holland (STScI), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 18:21:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible source coincident with NGC1495 (trigger=594286). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 59.640, -44.453, which is RA(J2000) = 03h 58m 34s Dec(J2000) = -44d 27' 10" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, the real-time TDRSS lightcurve does not show anything. The XRT began observing the field at 18:28:34.6 UT, 398.5 seconds after the BAT trigger. No source was detected in 1.0 ks of promptly downlinked data, which covered 98% of the BAT error circle. UVOT took a finding chart exposure of 150 seconds with the White filter starting 401 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Due to the low significance of this detection (5.92 sigma) the lack of an XRT or UVOT detection, and the lack of previous activity from this galaxy, there is a low likelihood that this is a real astrophysical source. Further analysis using the full ground-linked data will be required. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16083 SUBJECT: Swift Trigger 595162: a possible GRB DATE: 14/04/08 17:57:13 GMT FROM: Scott Barthelmy at NASA/GSFC V. D'Elia (ASDC), S. D. Barthelmy (GSFC), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 17:21:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible source near the known galaxy A0732-5019 (trigger=595162). Swift did not do an immediate slew because of an observing constraint. The BAT on-board calculated location is RA, Dec 113.599, -50.408, which is RA(J2000) = 07h 34m 24s Dec(J2000) = -50d 24' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, the real-time TDRSS light curve does not show anything significant. Due to a delayed slew, there are no immediate data from the XRT or UVOT instruments. We will report on those data when they become available. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16092 SUBJECT: Fermi418277210: iPTF optical observations DATE: 14/04/10 02:32:55 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), S. B. Cenko (NASA/GSFC), M. M. Kasliwal (Carnegie Observatories/Princeton), Adam Waszczak (Caltech), Sagi Ben-Ami (Weizmann), Joel Johansson (Stockholm University), and Avishay Gal-Yam (Weizmann) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: We have searched for optical counterparts of Fermi GBM trigger Fermi418277210 (2014-04-04 04:06:47.51) using the Palomar 48-inch Oschin telescope (P48). Based on the last automated Fermi ground software localization sent at 04:07:29, we began observing 10 fields covering 73 deg2, 12 minutes after the trigger. Since the final Fermi localization sent at 05:16:07 differed by 3 deg (well within the 1-sigma statistical-only uncertainty), we observed five more fields for a total area of 109 deg2. We estimate a 68% chance that one of these 15 fields contains the location of the source. Sifting through candidate variable sources using image subtraction and standard iPTF vetting procedures including photometry with the robotic Palomar 60" telescope (P60), we detected several optical transients, none of which showed evidence of significant fading. For the following sources, we obtained spectra with the Double Spectrograph (DBSP) on the Palomar 200" Hale telescope (P200): 14ain, detected at r = 18.67 +/- 0.03 mag and possibly rising, coincident with galaxy SDSS J111725.00+293457.4, identified as SN Ia, at z = 0.08, also reported by MASTER (Rufanov et al. 2014, ATel 6055), at the coordinates: RA(J2000) = 11h 17m 25.04s (169.354352 deg) Dec(J2000) = +29d 34' 58.3" (+29.582861 deg) 14ait, detected at r = 20.5 +/- 0.1 mag, on the outskirts of the galaxy SDSS J113303.95+330719.3, with the nebular spectrum of an old SN Ib/c at z = 0.039, at the coordinates: RA(J2000) = 11h 33m 04.04s (173.266841 deg) Dec(J2000) = +33d 07' 23.9" (+33.123292 deg) 14aiz, detected at r = 19.28 +/- 0.04 mag, coincident with the z=0.09701 galaxy SDSS J111407.50+390243.0, with an inconclusive spectrum showing only host light, at the coordinates: RA(J2000) = 11h 14m 07.28s (168.530319 deg) Dec(J2000) = +39d 02' 43.2" (+39.045337 deg) The following transient candidates were placed on the P200 queue, but not observed due to other higher-priority targets: 14aim, detected at r = 19.68 +/- 0.06 mag and coincident with the galaxy SDSS J114155.45+351813.9, at the coordinates: RA(J2000) = 11h 41m 55.57s (175.481562 deg) Dec(J2000) = +35d 18' 14.9" (+35.304133 deg) 14aip, detected at r = 19.40 +/- 0.05 mag and rising, clearly offset from the galaxy SDSS J111215.58+313056.2, at the coordinates: RA(J2000) = 11h 12m 16.02s (168.066732 deg) Dec(J2000) = +31d 30' 57.9" (+31.516089 deg) 14aiq, detected at r = 20.62 +/- 0.17 mag, coincident at the galaxy SDSS J111506.79+292025.1, at the coordinates: RA(J2000) = 11h 15m 06.89s (168.778719 deg) Dec(J2000) = +29d 20' 24.0" (+29.340007 deg) 14ais, detected at r = 20.33 +/- 0.08 mag, with no clearly associated host in SDSS, at the coordinates: RA(J2000) = 11h 51m 08.46s (177.785253 deg) Dec(J2000) = +31d 17' 03.2" (+31.284218 deg) 14aiu, detected at r = 20.20 +/- 0.14 mag and apparently hostless, at the coordinates: RA(J2000) = 11h 15m 09.30s (168.788748 deg) Dec(J2000) = +34d 26' 35.8" (+34.443280 deg) 14aiy, detected at r = 20.30 +/- 0.09 mag, coincident with the galaxy SDSS J114936.42+374417.3, at the coordinates: RA(J2000) = 11h 49m 36.47s (177.401968 deg) Dec(J2000) = +37d 44' 18.2" (+37.738379 deg) Due to the relative promptness of our first 10 observations, we were concerned that a bright (r <~ 14 mag) afterglow would have saturated on the P48 CCD and have been missed by our automated image subtraction pipeline. We therefore also visually inspected the 110 single-chip images from the first epoch of observations. We found no saturated objects that were absent from both the SDSS and the USNO-B1.0 catalogs. We also performed a semi-automated search over all of the P48 source extractions that contained saturated pixels. There were 6579 saturated objects, of which all were either present in the USNO-B1.0 catalog or clearly visible in archival SDSS images. The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi418277210.pdf shows the fifteen P48 fields (dark gray: the 10 prompt fields, light gray: the remaining 5) in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16094 SUBJECT: Swift-BAT trigger 595162 is noise DATE: 14/04/10 17:18:14 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), M. Chester (PSU), D. N. Burrows (PSU), D. M. Palmer (LANL), and D. Malesani (DARK/NBI), report on behalf of the Swift Team: At 17:21:40 08 Apr 2014 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=595162). This was a sub-threshold trigger due to a spatially coincident location with the known galaxy A0732-5019. Analysis using the fully downlinked event-by-event data does not show any significant source. XRT observations consisted of only 31s of valid data, because the star tracker was not able to get a lock because there were too few stars. Observations began about 1 hour after the trigger, and no new source is detected in the field. The UVOT images were trailed, also due to the star tracker loss of lock. Quantitative analysis is not possible; visual comparison with the DSS does not reveal any new sources. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16095 SUBJECT: Swift Trigger 595345 is not an astrophysical source DATE: 14/04/10 17:47:19 GMT FROM: David Palmer at LANL W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), S. B. Cenko (GSFC), V. D'Elia (ASDC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 17:20:28 UT, the Swift Burst Alert Telescope (BAT) triggered and found an image peak in the vicinity of NGC 4457 (trigger=595345). Swift slewed immediately to the BAT position. The BAT on-board calculated location is RA, Dec 187.132, +3.480 which is RA(J2000) = 12h 28m 32s Dec(J2000) = +03d 28' 47" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, nothing of note is found in the BAT light curve. The XRT began observing the field at 17:22:21.6 UT, 113.5 seconds after the BAT trigger. No source was detected in 1.2 ks of promptly downlinked data. UVOT took a finding chart exposure of 150 seconds with the White filter starting 117 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Due to the low significance of the BAT peak (6.51 sigma) in an image trigger, the lack of a corresponding rate increase, the large distance between the image peak and the potential host galaxy (0.149 degrees), and the lack of an XRT detection, we believe that this trigger was a noise peak and not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16098 SUBJECT: Swift Trigger 595616: a possible GRB DATE: 14/04/13 00:29:27 GMT FROM: Valerio D'Elia at ASDC V. D'Elia (ASDC), S. T. Holland (STScI), L. Izzo (URoma/ICRA), F. E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 00:09:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140413A (trigger=595616). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 65.449, -51.205 which is RA(J2000) = 04h 21m 48s Dec(J2000) = -51d 12' 17" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger and we cannot say much about the light curve. However, since it is 12.5 sigma detection at 64 sec exposure in the image domain, it is likely to be real. Due to an observing constraint, Swift will not slew until T0+33.6 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16135 SUBJECT: Swift Trigger 596641 is not a GRB DATE: 14/04/21 01:07:59 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), S. T. Holland (STScI), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 00:37:24 UT, the Swift Burst Alert Telescope (BAT) triggered on something which is not likely astrophysical (trigger=596641). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 336.363, +3.636, which is RA(J2000) = 22h 25m 27s Dec(J2000) = +03d 38' 10" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As per usual for an image trigger, the TDRSS real-time light curve does not show anything significant. The XRT began observing the field at 00:39:53.6 UT, 149.5 seconds after the BAT trigger. No source was detected in 862 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 153 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.10. Due to the lack of a BAT rate trigger, the marginal detection (7.0 sigma) in the BAT image, and the lack of a source in the XRT and UVOT data, we doubt that this is an astrophysical source. Further analysis will require the full ground downlinked data. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16158 SUBJECT: Swift Trigger 596958 is probably the flare star: DG CVn DATE: 14/04/23 21:41:04 GMT FROM: Kim Page at U.of Leicester V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 21:07:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located an X-ray source (trigger=596958). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 202.928, +29.258 which is RA(J2000) = 13h 31m 43s Dec(J2000) = +29d 15' 30" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the BAT light curve shows no significant structure. This is a 15-50 keV trigger with a duration of 64 seconds. The XRT began observing the field at 21:09:05.1 UT, 117.0 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 202.9436, 29.2763 which is equivalent to: RA(J2000) = +13h 31m 46.46s Dec(J2000) = +29d 16' 34.7" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 82 arcseconds from the BAT onboard position, within the BAT error circle. This position is 2.9 arcsec from that of the known flare star DG CVn, and 1.1 arcseconds from that of a known X-ray source, 3XMM J133146.5+291635 in the XMM-NEWTON XMMSSC catalogue. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 4.10e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 125 seconds after the BAT trigger. UVOT sees a very bright saturated source near the XRT position. Because of coincidence loss, it is difficult to accurately determine the position or count rate. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16159 SUBJECT: Swift Trigger 596958 is positionally consistent with V* DG CVn/2XMM J133146.4+291635 DATE: 14/04/23 22:15:11 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), C.-H. Bai, X. Zhang, A. Esamdin, L. Ma (XAO) report: We observed the BAT/XRT field of the Swift Trigger 596958 using the 1m telescope located at Nanshan, Xinjiang, China. Three 120s R-band frames were obtained in a seeing of ~2 aecsec, starting at 21:41:20 UT on 2014-03-24. The XRT error circle is nicely on the central part of the very bright flare star V* DG CVn, and the 2XMM J133146.4+291635 X-ray source is just within the XRT error circle (using the SIMBAD database). We think V* DG CVn and 2XMM J133146.4+291635 are the identical object. Comparing the DSS II, SDSS DR10, and Nanshan images, it's clear that the star has a proper motion towards the South-West direction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16183 SUBJECT: Trigger 597570: Swift detection of SGR 1806-20 DATE: 14/04/29 13:32:17 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. K. Cannizzo (NASA/UMBC), V. D'Elia (ASDC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), M. H. Siegel (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team: At 13:13:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1806-20 (trigger=597570). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 272.159, -20.404 which is RA(J2000) = 18h 08m 38s Dec(J2000) = -20d 24' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single spike with a duration of about 0.128sec. The peak count rate was ~11,000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 13:14:29.8 UT, 61.7 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 272.1632, -20.4116 which is equivalent to: RA(J2000) = 18h 08m 39.16s Dec(J2000) = -20d 24' 41.7" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 30 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.1 arcsec from the known position of SGR 1806-20. No spectrum from the promptly downlinked event data is yet available to determine the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 63 seconds after the BAT trigger. No credible optical counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The last previous detection of this Soft Gamma Repeater by BAT was on April 5, 2014. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16204 SUBJECT: Swift Trigger 597860 is probably not a GRB DATE: 14/05/02 14:33:31 GMT FROM: David Palmer at LANL V. Mangano (PSU), M. M. Chester (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 14:13:56 UT, the Swift Burst Alert Telescope (BAT) triggered on a peak in an image (trigger=597860). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 199.681, -35.631 which is RA(J2000) = 13h 18m 43s Dec(J2000) = -35d 37' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, there is no obvious variation in the BAT light curve. The XRT began observing the field at 14:16:14.9 UT, 139.0 seconds after the BAT trigger. No source was detected in 772 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 142 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Due to the marginal detection in BAT (7.06 sigma) with no corresponding rate increase, and the lack of a detection in XRT and UVOT, we believe that this is probably not an astrophysical source. Final determination of the reality of the source will require the full downlinked data. Burst Advocate for this burst is V. Mangano (vxm22 AT psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16238 SUBJECT: VHE gamma-ray observations by MAGIC of SWIFT Trigger 596958 DATE: 14/05/09 16:22:01 GMT FROM: Razmik Mirzoyan at MPI/MAGIC On 23th April 2014 at 21:08:26 UT, the MAGIC telescopes received a GRB-like event alert from Swift (D'Elia et al., GCN16158). It was later pointed out that this event was probably not due to a GRB but to a flaring star (Xu et al., GCN16159; Drake et al., ATel 6121). The MAGIC telescopes started observations of the transient event at 21:08:54 UT, about 30s after the alert was received, and kept collecting data for the next 3.3h. Data were taken in dark-night and under excellent weather conditions, at medium-low zenith angles (below 45deg). A preliminary analysis gave an integral flux upper limit of 1.2e-11 cm-2 s-1 above E>200 GeV at 95% c.l., corresponding to 5.3% of the Crab Nebula flux above 200 GeV, assuming a Crab-like spectral index. The intra-minute light-curve above 200 GeV did not show any hint of transient signal. The MAGIC collaboration is open to collaborate with other teams on this observation. MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to more than 50 TeV. Questions regarding the MAGIC observations should be directed to Razmik Mirzoyan ([1]Razmik.Mirzoyan@mpp.mpg.de) or Alessandro Carosi ([2]alessandro.carosi@oa-roma.inaf.it) and Saverio Lombardi ([3]saverio.lombardi@pd.infn.it). This message is quotable in publications -Razmik Mirzoyan, on behalf of the MAGIC Collaboration //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16239 SUBJECT: MAGIC upper limit on the transient from SWIFT Trigger 596958 DATE: 14/05/09 16:29:45 GMT FROM: Razmik Mirzoyan at MPI/MAGIC On 23th April 2014 at 21:08:26 UT, the MAGIC telescopes received a GRB-like event alert from Swift (D'Elia et al., GCN16158). It was later pointed out that this event was probably not due to a GRB but to a flaring star (Xu et al., GCN16159; Drake et al., ATel 6121). The MAGIC telescopes started observations of the transient event at 21:08:54 UT, about 30s after the alert was received, and kept collecting data for the next 3.3h. Data were taken in dark-night and under excellent weather conditions, at medium-low zenith angles (below 45deg). A preliminary analysis gave an integral flux upper limit of 1.2e-11 cm-2 s-1 above E>200 GeV at 95% c.l., corresponding to 5.3% of the Crab Nebula flux above 200 GeV, assuming a Crab-like spectral index. The intra-minute light-curve above 200 GeV did not show any hint of transient signal. The MAGIC collaboration is open to collaborate with other teams on this observation. MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to more than 50 TeV. Questions regarding the MAGIC observations should be directed to Razmik Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de) or Alessandro Carosi (alessandro.carosi@oa-roma.inaf.it) and Saverio Lombardi (saverio.lombardi@pd.infn.it). This message is quotable in publications -Razmik Mirzoyan, on behalf of the MAGIC Collaboration ---------------------------------------------------------------------------- ------------------------------ Regards ---Razmik Mirzoyan-- ----------------------------------------------- There are more important things in life than constantly increasing its speed. Mahatma Gandhi ----------------------------------------------- Razmik Mirzoyan Senior Astrophysicist Max-Planck-Institute for Physics (Werner-Heisenberg-Institute) Foehringer Ring 6 80805 Munich Germany -------------------------------------------------------------------- Tel.: (+49)(89)-323-54-328 Fax: (+49)(89)-322-67-04 http://wwwmagic.mpp.mpg.de; www.mpp.mpg.de e-mail: Razmik.Mirzoyan@mpp.mpg.de mostly @ N: 48.18405; E: 11.61184; 534m a.s.l. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16245 SUBJECT: Fermi GBM Trigger 140429551 - Detection of a burst from SGR 1806-20 DATE: 14/05/12 16:15:28 GMT FROM: Matthew Stanbro at UAH/Fermi SUBJECT: Fermi GBM Trigger 140429551 - Detection of a burst from SGR 1806-20 M. Stanbro (UAH) and G. Younes (USRA/MSFC) report on behalf of the Fermi GBM Team: "At 13:13:28.49 UT on 29 April 2014, the Fermi Gamma-Ray Burst Monitor triggered on a burst from SGR 1806-20, which was also detected by Swift/BAT (Barthelmy et. al. 2014, GCN 16183). The GBM on-ground location is consistent with the Swift position. The burst consists of a single pulse, with a duration of T90 = 0.13 +/- 0.02 s. The burst is well-fit with a power law function with an exponential high-energy cutoff parameterized as Epeak = 25 +/- 2 keV and an Index -0.3 +/- 0.5. The corresponding peak flux integrated over 4ms (8-200 keV) is (2.6 +/- 0.5)E-07 erg/s/cm^2. The fluence during T0-0.032s to T0+0.104s is (1.17 +/- 0.08)E-07 erg/cm^2. The analysis results presented above are preliminary." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16268 SUBJECT: Trigger 599041: Swift detection of SFXT IGR J16479-4514 DATE: 14/05/15 10:07:32 GMT FROM: David Palmer at LANL P. Romano (INAF-IASFPA) report on behalf of the Swift Team: At 09:52:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located the SFXT IGR J16479-4514 (trigger=599041). Due to higher priority follow-up of GRB 140515A, Swift did not slew to this object. The BAT on-board calculated location is RA, Dec 252.039, -45.200 which is RA(J2000) = 16h 48m 09s Dec(J2000) = -45d 12' 00" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for imaging triggers, this event is not obvious in the on-board BAT light curve. Previously, Swift observed flares from this Supergiant Fast X-ray Transient on 2005 August 30 (Sidoli et al. 2008, ApJ, 687, 1230), 2006 May 20 (Markwardt & Krimm 2006, ATel #816), 2006 June 24, 2007 July 29, 2008 March 19 (Romano et al. 2008, ApJ, 680, L137), 2008 May 21, and 2009 January 29 (Romano et al. 2009, MNRAS, 399, 2021). The historical light curve from the BAT hard X-ray transient monitor (Krimm et al, 2013, ApJS, 209, 14; 15-50 keV) can be found at http://swift.gsfc.nasa.gov/docs/swift/results/transients/weak/IGRJ16479-4514/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16325 SUBJECT: Swift trigger 599860 probably not real DATE: 14/05/24 14:03:58 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), L. Izzo (URoma/ICRA), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 13:25:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140524A (trigger=599860). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 53.405, -36.096 which is RA(J2000) = 03h 33m 37s Dec(J2000) = -36d 05' 46" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is a low-threshold trigger due to its position matching a nearby galaxy in the on-board catalog. As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 13:28:12.0 UT, 144.2 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 53.4016, -36.1396 which is equivalent to: RA(J2000) = 03h 33m 36.39s Dec(J2000) = -36d 08' 22.5" with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 157 arcseconds from the BAT onboard position, within the BAT error circle; and in the nearby AGN NGC1365 in the BAT catalogue. The XRT position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.0 arcseconds from that of a known X-ray source: 3XMM J033336.4-360825 in the XMM-NEWTON XMMSSC catalogue which we assume is the AGN X-ray emission from the galaxy. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.39 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 148 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16330 SUBJECT: Swift detection of SFXT IGR J17544-2619 DATE: 14/05/25 22:51:03 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), V. D'Elia (ASDC), A. Y. Lien (NASA/GSFC/ORAU), V. Mangano (PSU), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 22:25:47 UT, the Swift Burst Alert Telescope (BAT) triggered twice on an SFXT IGR J17544-2619, (triggers=599954 and 599955). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 268.617, -26.339, which is RA(J2000) = 17h 54m 28s Dec(J2000) = -26d 20' 19" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers the real-time BAT light curve shows nothing significant. The XRT began observing the field at 22:33:07.4 UT, 439.5 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 268.6050, -26.3322 which is equivalent to: RA(J2000) = +17h 54m 25.20s Dec(J2000) = -26d 19' 55.9" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 45 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 3.58e-09 erg cm^-2 s^-1 (0.2-10 keV). Previously, Swift observed bright flares from this source on 2007 November 8 (Krimm et al. 2007, Atel #1265), 2008 March 31 (Sidoli et al. 2009, ApJ, 690, 120), 2008 September 4 (Sidoli et al. 2009, MNRAS, 397, 1528), 2009 March 15 (Krimm et al. 2009, Atel #1971), 2009 June 6 (Romano et al. 2011, MNRAS, 410, 1825), 2010 March 4 (Romano et al. 2011, MNRAS, 412, L30), 2011 March 24 (Farinelli et al. 2012, MNRAS, 424, 2854), 2012 April 12 (Romano et. al. 2012, ATel #4040), 2012 July 24 (Romano et al. 2012, ATel #4275), 2013 June 28 (Romano et al. 2013, ATel #5179), and 2013 September 11 (Romano et al. 2013, ATel #5388). The historical light curve from the BAT hard X-ray transient monitor (Krimm et al, 2013, ApJS, 209, 14; 15-50 keV) can be found at http://swift.gsfc.nasa.gov/docs/swift/results/transients/weak/IGRJ17544-2619 . //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16331 SUBJECT: Fermi GBM trigger 422752719/ 140525971 is not a GRB DATE: 14/05/26 00:48:33 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH), reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 422752719/ 140525971 at 23:18:36.74 UT on 25 May 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16332 SUBJECT: Swift detection of a bright X-ray source in M31 DATE: 14/05/27 22:15:08 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), S. B. Cenko (GSFC), V. D'Elia (ASDC), D. Malesani (DARK/NBI), V. Mangano (PSU), F. E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 21:24:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source in M31 (NGC224) (trigger=600114). Swift slewed immediately to the target. The BAT on-board calculated location is RA, Dec 10.402, +41.556, which is RA(J2000) = 00h 41m 37s Dec(J2000) = +41d 33' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger of 64 second duration, with significance 6.18 sigma, which is lower than typical blind detection significance. The BAT light curve does not show obvious structure, which is typical for image triggers. The XRT began observing the field at 21:27:05.4 UT, 157.5 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 10.4292, 41.5734 which is equivalent to: RA(J2000) = 00h 41m 43.02s Dec(J2000) = +41d 34' 24.3" with an uncertainty of 2.9 arcseconds (radius, 90% containment). This location is 96 arcseconds from the BAT onboard position, within the BAT error circle. The XRT position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 4.0 arcseconds from that of a known X-ray source: 3XMM J004143.0+413420 in the XMM-NEWTON XMMSSC catalogue. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.81 x 10^21 cm^-2 (Willingale et al. 2013). The associated source in the 3rd XMM catalog has a spectrum and variability which is consistent with a low-mass X-ray binary (Stiele 2010). However, the target is also spatially consistent with a globular cluster FMZ2005-7 of M31. There may be multiple X-ray binaries within the same globular cluster. The XRT count rate is approximately 30 counts per second. Assuming a typical conversion factor to flux, the 0.3-10 keV flux is approximately 1e-9 erg/cm2/s (uncertain to a factor of 2x). At the distance of Andromeda, this would be a luminosity of 7e40 erg/s (uncertain to the same factor). This luminosity is clearly super-Eddington for a ~solar mass compact object, so either the object is of ULX class, or it is significantly beamed. UVOT took a finding chart exposure of 150 seconds with the White filter starting 162 seconds after the BAT trigger. UVOT detects a 16.9 mag source at the position RA (J2000) = 00:41:43.10 = 10.42957 Dec(J2000) =+41:34:20.4 = 41.57232 with a 90% confidence error radius of 0.61 arc sec. This position is 4 arc seconds from the center of the XRT error circle and consistent with the position of the globular cluster. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16333 SUBJECT: Swift Trigger 600114 in M31: Archival and Prompt UVOT Imaging DATE: 14/05/28 03:19:10 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team: Archival UVOT images of the transient reported in M31 (Barthelmy et al., GCN Circ. 16332) from July 2009 and November 2011 show the known globular cluster B045-G108 at the reported UVOT position, 4.5 arc-seconds from the position of the X-ray transient. Although a direct comparison is not possible at this time, we measure the following magnitudes for the object, before and after the trigger, using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373): Archival: Filter Mag uvw2 19.4+-0.1 uvm2 19.6+-0.2 uvw1 18.2+-0.1 Prompt: u 17.1+-0.2 white 16.9+-0.1 The post-explosion u magnitude would be roughly consistent with the pre-explosion NUV magnitudes given the SED of a typical M31 globular cluster. However, without processing of the full post-outburst data set, we cannot determine if the source has varied in the UV since 2011. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16334 SUBJECT: Swift Trigger 600114: Preliminary BAT analysis DATE: 14/05/28 05:58:06 GMT FROM: Craig Markwardt at NASA/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-120 to T+180 sec from a recent telemetry downlink, we report preliminary analysis of BAT trigger 600114, tentatively associated with the M31 galaxy (Barthelmy, et al., GCN Circ. 16332). The BAT ground-calculated position is RA, Dec = 10.371, 41.520 deg which is RA(J2000) = 00h 41m 29.0s Dec(J2000) = +41d 31' 11.7" with an uncertainty of 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 50%. The mask-weighted light curve is consistent with a sharp rise (~10 sec rise time) near T+0sec, followed by a ~60 sec decay. The excess counts are primarily in the 15-50 keV band. T90 (15-350 keV) is 55.2 +- 15.9 sec (estimated error including systematics). The time-averaged spectrum from T-4 to T+55 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.35 +- 0.57. The fluence in the 15-150 keV band is (3.1 +- 1.1) x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+22.42 sec in the 15-150 keV band is 0.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. We caution that this is a faint BAT transient and the significance is lower than typical for GRBs. We urge confirmation at other wavelengths. Significance, light curve and spectral properties may be revised after further refined analysis. If confirmed as real and associated with the M31 galaxy at a distance of 778 kpc, the mean luminosity averaged over the T90 duration in the 15-150 keV band would be 2-6 x 10^41 erg/s. Such a luminosity, if isotropic, would be highly super Eddington for a 1 solar mass object (by a factor in the 2000-5000 range). Alternatively, the source could be highly beamed in our observer direction. Although either interpretation suggests a tantalizingly energetic event as the progenitor, we again urge caution until the presence of a bright source at this location is confirmed independently. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/600114/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16335 SUBJECT: Swift Trigger 600114: Optical spectroscopy from GTC DATE: 14/05/28 07:54:06 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC/UPV-EHU), A. de Ugarte Postigo (IAA-CSIC/DARK-NBI), C. Thöne (IAA-CSIC), T. Muñoz-Darias (Oxford Uni.), R. Sanchez-Ramirez (IAA-CSIC), R. Scarpa (IAC-ULL), report on behalf of a larger collaboration. We have obtained spectroscopic data of the optical counterpart of the bright X-ray source in M31 (Barthelmy et al. GCNC 16332) with the 10.4m GTC telescope. Observations started on May 28.17800 UT, 6.9 hr post burst. Three 600s spectra where taken with the R1000B grism yielding a spectral range between 3700 and 7700 A at a resolution of ~1000. The slit was positioned within the central light of the globular cluster that is probably associated with the event (FMZ2005-7). A preliminary reduction of the spectra reveals several absorption lines, including Na I, the Balmer series and Ca II, all blue-shifted consistently with the 427 km/s reported by Kang et al. 2012 (ApJS, 199, 37). A very preliminary analysis shows no excess with respect what we would expect from the globular cluster emission. A deeper analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16336 SUBJECT: Swift trigger 600114 is not an outbursting X-ray source DATE: 14/05/28 07:57:12 GMT FROM: Kim Page at U.of Leicester K.L. Page, P.A. Evans (U. Leicester), D.N. Burrows (PSU), V. D'Elia (ASDC) and A. Maselli (INAF-IASFPA) report on behalf of the Swift-XRT team: We have re-analysed the prompt XRT data on Swift trigger 600114 (GCN Circ. 16332), taking advantage of the event data. The initial count rate given in GCN Circ. 16332 was based on raw data from the full field of view, without X-ray event detection, and therefore may have been affected by other sources in M31, as well as background hot pixels. Analysis of the event data (not fully available at the time of the initial circular) shows the count rate of the X-ray source identified in GCN Circ. 16332 to have been 0.065 +/- 0.012 count s^-1, consistent with the previous observations of this source [see the 1SXPS catalogue (Evans et al. 2014): http://www.swift.ac.uk/1SXPS/1SXPS%20J004143.1%2B413420. We therefore do not believe this source to be in outburst. Instead, it was a serendipitous constant source in the field of view of a BAT subthreshold trigger. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16337 SUBJECT: Swift Trigger 600114 in M31: UVOT Observations DATE: 14/05/28 14:40:40 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and J. K. Cannizzo (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations 162s after the trigger in M31 reported by Barthelmy et al. (GCN Circ. 16332). At the position given in that GCN we are now able to report the full range of magnitudes from the initial data. The source does not seem to be fading and these magnitudes are consistent with the archival data reported by Siegel (GCN Circ. 16333). This is consistent with the conclusion drawn by Page et al. (GCN Circ. 16336). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 162 312 147 16.83 ± 0.03 v 5124 5324 197 15.88 ± 0.05 b 5944 6144 197 16.79 ± 0.04 u 320 570 246 17.00 ± 0.06 w1 5534 5734 197 18.33 ± 0.2 m2 5329 6964 393 19.44 ± 0.3 w2 4919 5119 197 19.55 ± 0.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16349 SUBJECT: Swift XRT is off-line DATE: 14/06/04 16:52:40 GMT FROM: David Burrows at PSU/Swift D. N. Burrows, J. A. Kennea, J. A. Nousek, and N. Gehrels report on behalf of the Swift team: At 00:23 UT on 4 June 2014, Swift XRT rebooted. Two attempts to recover the instrument to normal operational status were unsuccessful. The instrument is currently operating in “Manual State” (a debugging/calibration state) but cannot currently be switched back into Auto State to collect normal science data. XRT data taken in Manual State look normal, indicating that the CCD and signal processing chain in the instrument are working correctly. We are working to restore the instrument to normal operating conditions at the earliest possible opportunity. The anomaly affects only the XRT instrument; the BAT and UVOT instruments are working normally and continue to collect data. The BAT will continue to detect new GRBs and transients and Swift will continue to slew to them, and the real-time notices will continue to be distributed by the GCN, but there will be no XRT data until the anomaly is resolved. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16352 SUBJECT: Swift Trigger 600914 is probably a noise fluctuation DATE: 14/06/05 23:23:03 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. A. Kennea (PSU), D. M. Palmer (LANL), M. C. Stroh (PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 23:06:51 UT, the Swift Burst Alert Telescope (BAT) triggered on probably noise in the image domain near the on-board catalog source NGC0746 (trigger=600914). Swift did not slew because of the Sun observing constraint. The BAT on-board calculated location is RA, Dec 29.393, +44.977, which is RA(J2000) = 01h 57m 34s Dec(J2000) = +44d 58' 36" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT real-time light curve does not show anything significant as is typical for image trigger. We will know more when the full data set is downlinked and analyzed. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16355 SUBJECT: Swift Trigger 600914 is noise DATE: 14/06/06 19:07:43 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) & H. A. Krimm (GSFC/USRA), (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we confirm that trigger #600914 (Barthelmy, et al., GCN Circ. 16352) is due to noise and is not astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16356 SUBJECT: Swift XRT status update DATE: 14/06/06 20:32:18 GMT FROM: David Burrows at PSU/Swift D. N. Burrows and J. A. Kennea report on behalf of the Swift XRT team: At about 15:22 UT today the Swift XRT instrument resumed observations in a somewhat degraded mode while we continue to investigate the underlying anomaly (GCN Circ. 16349). Our intention is to remain in this mode at least through the end of Monday June 9. XRT is now operating in a special calibration mode that was used occasionally in the first several years of operations. In this mode XRT is being manually commanded for each observation, through commands embedded in the uploaded spacecraft timeline. This differs from its normal mode of automated robotic observations in several key respects: 1) XRT will observe each target in a predefined instrument mode, either Photon Counting (PC) or Windowed Timing (WT). It will not switch automatically between modes based on the observed count rate, as it usually does. 2) All targets for which WT mode was requested will be observed in WT mode. WT mode appears to be operating normally and the data should not be compromised in comparison to our normal operating mode. 3) All targets for which Auto or PC mode was requested will be observed in a modified PC mode. This differs from our normal PC mode in that the observations will be taken without bias frame subtraction. The bias level correction applied by our normal ground processing software does a good job of compensating for the lack of on-board bias subtraction. However, we have also had to raise the lower energy threshold to eliminate hot pixels and other detector artifacts in the downlinked data; this imposes a low energy cutoff of about 0.5 keV and affects the spectral calibration. A calibration observation of Cas A conducted yesterday suggests that this mode works well, but there appears to be a larger systematic uncertainty in the energy calibration than usual (of order 20 eV). Source positions determined from PC mode data should have the normal accuracy, but the spectral data and flux determination will not be properly calibrated and should be used with caution. Note that bright sources will be saturated in PC mode. 4) XRT will operate and return data following BAT triggers, but will not produce its usual automated response. This means that XRT will not provide on-board centroid positions or the prompt data that normally allows us to determine accurate GRB positions within minutes of the BAT detection. Instead, XRT will continue to collect data in whatever mode the pre-planned observation was in. In most cases this will be PC mode and XRT position information will eventually become available once the full data set is downloaded to the ground and processed. In the event that XRT happens to be in WT mode when a burst occurs, no position information will be produced. We emphasize that the XRT team is continuing to acquire diagnostic information in an effort to determine the root cause of the original anomaly and to allow us to return to normal operations as soon as possible. During this period of anomalous operations, some observations are being terminated to permit diagnostic and calibration information to be collected from the instrument. We thank you for your patience as we continue to recover the instrument to its normal configuration. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16360 SUBJECT: Fermi423717114: iPTF optical transient candidates DATE: 14/06/07 03:08:08 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), M. M. Kasliwal (Carnegie Observatories/Princeton), and S. B. Cenko (NASA/GSFC) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: Fermi GBM reported trigger 423717114 at 2014-06-06 03:11:51.86 UT. We have searched for optical counterparts using the Palomar 48-inch Oschin telescope (P48). Based on the final Fermi GBM localization, we observed 10 fields covering 73 deg2, with an estimated 56% chance of containing the true location of the event. Sifting through candidate variable sources using image subtraction and standard iPTF vetting procedures, we detected several optical transients. iPTF14bfu has no previous detections in iPTF from 2013-05-23 through 2013-10-13, and no obvious host associations. From 4.3 to 5.5 hours after the burst, it faded from r = 19.89 +/- 0.10 to 20.32 +/- 0.14 mag, fitting a power law of alpha = -1.6 +/- 0.7 relative to the time of the GBM trigger. It is at the coordinates: RA(J2000) = 21h 52m 29.97s (328.124877 deg) Dec(J2000) = +32d 00' 50.6" (+32.014053 deg) iPTF14bfw is coincident with the faint galaxy SDSS J220322.02+291451.1. It was at r = 19.96 +/- 0.06 and possibly fading, at the coordinates: RA(J2000) = 22h 03m 22.04s (330.841830 deg) Dec(J2000) = +29d 14' 51.8" (+29.247730 deg) iPTF14bgc, was at r = 18.44 +/- 0.02 and possibly fading. It is coincident with a r = 21.07 +/- 0.08 mag point source in our coadded reference image composed of exposures from 2013-07-31 through 2013-09-24. It is at the coordinates: RA(J2000) = 21h 45m 36.14s (326.400599 deg) Dec(J2000) = +32d 08' 57.9" (+32.149426 deg) iPTF14bga, was at r = 19.75 +/- 0.06 mag and possibly fading. It is coincident with a r = 20.42 +/- 0.17 mag point source in our reference image composed of exposures from 2011-07-29 through 2011-10-20. It is a the coordinates: RA(J2000) = 22h 12m 43.78s (333.182423 deg) Dec(J2000) = +33d 39' 43.7" (+33.662146 deg) Further observations are planned, and are encouraged to determine the nature of these candidates and determine if any of them are indeed associated with the Fermi trigger. The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi423717114.pdf shows the locations of our candidates and the ten P48 fields in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours. We thank the Fermi-GBM team for sharing their detailed localizations with us. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16362 SUBJECT: Fermi 423717114: Additional P48 and P60 observations DATE: 14/06/07 12:01:45 GMT FROM: Daniel Perley at Caltech D. A. Perley and L. Singer (Caltech) report on behalf of a larger collaboration: We re-imaged the same ten P48 fields near the center of the error circle of Fermi trigger 423717114 (Singer et al., GCN 16360) between 09:28:30 through 09:42:30 UT on the night of 2014-06-07. iPTF14bfw and iPTF14bga have not faded relative to our observations during the previous night. For iPTF14bgc, we measure R = 20.68 +/- 0.21, consistent with the point-like counterpart in our reference images but significantly fainter than the previous night. A power law fit to the decay gives a temporal index of alpha = -1.1 +/- 0.1. We do not detect iPTF14bfu in our P48 image with a limiting magnitude of R ~ 21.1. Further imaging was obtained with the Palomar 60-inch telescope on two epochs, starting at 07:47:45 and 10:47:31, respectively. We acquired a series of seven 180-second images in r-band and five 180-second images in i-band in the first epoch, and a series of seven 180-second images in r-band during the second epoch. We detect the transient in a combined stack of all exposures in each band/epoch. Calibrating relative to USNO-B1.0 stars in the image, we measure magnitudes of: r = 21.1 +/- 0.2 (t_mid = 28.78 hr) i = 21.0 +/- 0.3 (t_mid = 29.12 hr) r = 21.4 +/- 0.2 (t_mid = 31.78 hr) Relative to the magnitudes presented by Singer et al., these observations suggest an average temporal index of only alpha~-0.5, much slower than observed during the first night. Further observations are ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16378 SUBJECT: Swift/XRT returns to normal observing DATE: 14/06/10 21:00:44 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea and D. N. Burrows (PSU) report on behalf of the Swift/XRT team: At 17:58UT on June 10th, 2014, Swifts X-ray Telescope (XRT) was commanded into Auto State, returning it to a normal observing setup. The mode of XRT operations described by GCN #16356 no longer applies. This means that Photon Counting mode data will now be taken with bias subtraction turned on and the low energy cut-off returned to the nominal value. XRT will produce prompt TDRSS GRB products for Swift/BAT detected bursts. Also we are no longer commanding observations manually, so GRBs and TOOs will be taken in the appropriate XRT mode. At this time we continue to investigate the cause of the anomaly. This may require short periods of downtime for XRT while we run diagnostic tests, which may interrupt some observations. We expect the overall downtime due to these tests to be low (<5%). We apologize in advance for any observations that are interrupted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16413 SUBJECT: Swift-BAT trigger 601928: Detection of a possible outburst from V490 Cep DATE: 14/06/17 07:34:51 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 06:37:31 UT, the Swift Burst Alert Telescope (BAT) triggered on a possible source (trigger=601928). Swift slewed immediately to the event. The BAT on-board calculated location is RA, Dec 324.790, +56.953 which is RA(J2000) = 21h 39m 10s Dec(J2000) = +56d 57' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is a very long image trigger with duration of 1088 s. As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 06:59:41.9 UT, 1330.1 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 324.8792, 56.9866 which is equivalent to: RA(J2000) = +21h 39m 31.01s Dec(J2000) = +56d 59' 11.8" with an uncertainty of 6.1 arcseconds (radius, 90% containment). This location is 212 arcseconds from the BAT onboard position. This position is 3.0 arcseconds from V490 Cep, a high mass X-ray binary, however it is more than 2-sigma away from the BAT position, and so possibly unrelated to the trigger. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 6.00e-10 erg cm^-2 s^-1 (0.2-10 keV). Because XRT centroided on the high mass X-ray binary V490 Cep, it is likely that this object is in outburst, and it is this which triggered the BAT. However we cannot rule out the possibility that BAT triggered on a GRB coincidentally close to V490 Cep on the sky. Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16414 SUBJECT: Swift trigger 601928 is V490 Cep: BAT+XRT refined analysis. DATE: 14/06/17 15:58:58 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester), A.P. Beardmore (U. Leicester), H. A. Krimm (CRESST/GSFC/USRA) and A. Y. Lien (GSFC/CRESST/UMBC) report on behalf of the Swift team: At 06:37:31 UT on 2014 June 17 Swift-BAT triggered on a source consistent with the location of V490 Cep (= Cep X-4 = Ginga 2138+56) which the MAXI team reported to be in outburst in ATEL #6212. This trigger was reported in GCN Circ. 16413. The refined BAT position is RA, Dec = 324.784, 56.949 deg which is equivalent to: RA(J2000) = 21h 39m 08.2s Dec(J2000) = +56d 56' 56.9" with an uncertainty of 4.1 arcmin, (radius, 90% confidence). The partial coding was 89%. XRT finds a single X-ray source in the BAT error circle, with an enhanced XRT position of RA,Dec= 324.87743, 56.98608 which is equivalent to: RA (J2000) = 21h 39m 30.58s Dec (J2000) = +56d 59' 09.9" with an uncertainty of 1.7 arcsec (radius, 90% confidence). This is 1 arcsec away from the catalogued position of V490 Cep in SIMBAD. This source has been regularly monitored by the BAT Transient Monitor (Krimm et al., 2013, ApJSS 209,14) and has been seen to be steadily rising, with an average flux at present of 80 mCrab. The observation which triggered BAT was that with the highest significance detection of this source by the BAT during the current outburst. The time-averaged BAT spectrum from T+0.00 to T+303.04 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 3.52 +/- 0.63. The fluence in the 15-150 keV band is 3.9 (+/- 1.1) e-7 erg cm^-2 The Windowed Timing mode XRT spectrum can be modelled with an absorbed power-law, with a photon index of 1.01 (+/- 0.05) and an absorption column of 1.32 (+0.10, -0.09) e22 cm^-2. The mean 0.3-10 keV count-rate is ~15 ct/sec, which is consistent with the MAXI-GSC count-rate of 0.11 ct/sec reported in ATEL #6212, assuming the WT mode spectrum. The X-ray data show clear signs of modulation, with a period of 66.58 +/- 0.22 s (90% confidence). Compared to the measurements reported in Wilson, Finger & Scott (1999, ApJ, 511, 367), this implies a spin-down rate of 1.3e-13 Hz/s; a factor of 3 higher than measured in that paper between 1993 and 1997. This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16425 SUBJECT: Fermi 424934131 / iPTF14cva: Discovery and Redshift of Optical Afterglow DATE: 14/06/20 16:59:04 GMT FROM: Mansi M. Kasliwal at Caltech/Carnegie M. M. Kasliwal (Carnegie Observatories/Princeton), S. B. Cenko (NASA/GSFC), and L. P. Singer (Caltech) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: Fermi GBM reported trigger 424934131 at 2014-06-20 05:15:28.02 UT. Starting 2014-06-20 05:25:25 UT (10 min after trigger), we began our search for optical counterparts using the Palomar 48-inch Oschin telescope (P48). Based on the the ground and final Fermi GBM localizations, we observed 20 fields covering 147 deg^2, with an estimated 59% chance of containing the true location of the event. Sifting through candidate transient sources using image subtraction and standard intermediate Palomar Transient Factory vetting procedures, we detected several optical transients. The fastest fading transient was: iPTF14cva, at the coordinates: RA(J2000) = 18h 47m 29.01s (281.870873 deg) Dec(J2000) = +49d 43' 51.7" (+49.731037 deg) iPTF14cva faded from R=17.6 mag to R=18.8 mag between 05:30 UT to 06:42 UT. We observed iPTF14cva with the Gemini Multi-Object Spectrograph mounted on the 8m Gemini North telescope beginning at 14:00 UT on 2014 June 20 (~ 8.8 hr after the GBM trigger). Two 900 s spectra were obtained, covering the wavelength range from 4000-9300 A. Super-imposed on a relatively flat continuum, we detect a number of strong absorption features, including Mg I, Mg II, Fe II, Al II, Si II, and Si II*, at a common redshift of z = 2.04. The detection of the fine structure Si II* feature, together with the lack of Ly-alpha absorption in the spectrum, imply that this is the redshift of the Fermi GBM GRB. In addition, we detect strong absorption features (Mg II, Fe II) from an intervening system at a redshift of z = 0.88. The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi424934131.pdf shows the locations of the afterglow and the 20 P48 fields in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours. We thank the Fermi-GBM team for promptly sharing their detailed localizations with us. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16429 SUBJECT: Konus-Wind observation of GRB DATE: 14/06/21 14:56:08 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lyssenko, and T. Cline on behalf of the Konus-Wind team, report: A long-duration, very intense GRB 140616C (IPN triangulation: Hurley et al., GCN 16427) triggered Konus-Wind at T0=81966.864 s UT (22:46:06.864). The burst light curve shows two separate multipeaked episodes: the first from ~T0-6 s to ~T0+12 s and the second longer and brighter from ~T0+68 s to ~T0+93 s. The total duration of the burst is ~105 s. The emission is seen up to ~10 MeV. As observed by Konus-Wind, the burst had a fluence of 1.1(-0.08,+0.08)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+72.832 s, of 2.25(-0.16,+0.16)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+97.792 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.15 (-0.15,+0.19), the high energy photon index beta = -2.37 (-0.13,+0.10), the peak energy Ep = 129 (-12,+13) keV, chi2 = 94/84 dof. The spectrum near the peak count rate (measured from T0+65.792 to T0+81.408 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.05 (-0.13,+0.13), the high energy photon index beta = -2.37 (-0.14,+0.09), the peak energy Ep = 169 (-15,+20) keV, chi2 = 114/97 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140619_T81966/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16442 SUBJECT: Fermi 425193729 / iPTF14cyb: Discovery of optical afterglow DATE: 14/06/23 13:58:46 GMT FROM: Varun Bhalerao at IUCAA V. B. Bhalerao (IUCAA), L. P. Singer (Caltech), M. M. Kasliwal (Carnegie Observatories/Princeton), S. B. Cenko (NASA/GSFC), A. Horesh (Weizmann Institute) and D. A. Perley (Caltech) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: Fermi GBM reported trigger 425193729 at 2014-06-23 05:22:06.600 UT. Starting 2014-06-23 05:33:07.776 UT (JD 2456831.73134, 11 min after trigger), we began our search for optical counterparts using the Palomar 48-inch Oschin telescope (P48). Based on the automated Fermi ground localization, we selected 10 fields covering an area of 74 deg^2. The final Fermi localization, available 2.6 hours after the trigger, differed in position by 13.4 deg. Based on the final localization and an empirical description of the systematic errors of the GBM localization (Paciesas et al. 2012, http://dx.doi.org/10.1088/0067-0049/199/1/18), we estimate a 4% chance that these fields contain the true location of the source. Sifting through candidate transient sources using image subtraction and standard intermediate Palomar Transient Factory vetting procedures, we detected several optical transients. The fastest fading transient was iPTF14cyb, at the coordinates: RA(J2000) = 15h 01m 53.42s (225.472574 deg) Dec(J2000) = +81d 11' 29.1" (+81.191410 deg) We note that the position of 1PTF 14cyb is consistent with both the iniital ground and final localizations. Measured R magnitudes of iPTF14cyb are JD R 2456831.73527 18.0 2456831.75906 19.3 2456831.78167 19.7 These are consistent with a power-law decay with index -0.93 +- 0.17. We observed iPTF14cyb with the Gemini Multi-Object Spectrograph mounted on the 8m Gemini North telescope beginning at 08:10 UT on 2014 June 23 (~ 2.8 hr after the GBM trigger). Two 900 s spectra were obtained, covering the wavelength range from 4000-9300 A. Super-imposed on a relatively flat continuum, we detect a number of strong absorption features, including Mg II, Fe II, Al II, Si II, Al III, C I, and C IV, at a common redshift of z = 1.92. The lack of Ly-alpha absorption in the spectrum suggests that this is the redshift of the Fermi GBM GRB. In addition, we detect strong absorption features (Mg II, Fe II) from an intervening system at a redshift of z = 1.06. The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi425193729.pdf shows the locations of the afterglow and the 10 P48 fields in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours. We have triggered follow-up observations with Swift, EVLA and CARMA. We encourage follow-up observations to confirm the nature of the source. We thank GoGo Inflight Wifi for internet at 10,000 feet. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16463 SUBJECT: Swift Trigger 602668 is probably not an astrophysical source DATE: 14/06/26 15:54:51 GMT FROM: David Palmer at LANL M. G. Bernardini (INAF-OAB), J. R. Cummings (NASA/UMBC), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), A. Melandri (INAF-OAB), K. L. Page (U Leicester), M. H. Siegel (PSU) and E. Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Swift Team: At 15:27:39 UT, the Swift Burst Alert Telescope (BAT) found a marginal- significance image peak with a location near to the galaxy NGC4215 (trigger=602668). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 183.900, +6.468 which is RA(J2000) = 12h 15m 36s Dec(J2000) = +06d 28' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). No BAT lightcurve data is immediately available, but the image was generated by schedule, and not as a result of a rate trigger. The XRT began observing the field at 15:40:01.0 UT, 741.3 seconds after the BAT trigger. No source was detected in 589 s of promptly downlinked data, which covered 91% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 744 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Due to the low significance of the peak (6.06 sigma), the lack of a corresponding rate trigger on this 8-minute untriggered image, the 6 arcminute offset of the peak from the galaxy, and the lack of confirmation by the XRT and UVOT, we believe that this event is a noise fluctuation in the image. Confirmation will require the full downlinked dataset. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16465 SUBJECT: Swift Trigger 602668: XRT and UVOT confirm is not astrophysical source DATE: 14/06/27 15:01:21 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri, P. D’Avanzo, M. G. Bernardini (INAF/OAB) and N. P. M. Kuin (UCL-MSSL) report on behalf of the Swift team: We have analysed 0.96 ks of Swift/XRT data for the BAT-detected trigger 602668 (Bernardini et al., GCN Circ. 16463), from 758 s to 1.73 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. No bright X-ray afterglow is detected within the BAT error circle. The 3 sigma upper limit is 4.1E-02 cts/s. The Swift/UVOT observed the field from 744 s to 1.73 ks after the BAT trigger. No optical afterglow is detected in the UVOT exposures. The lack of an XRT or UVOT detection confirms that this trigger was not an astrophysical source. This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16497 SUBJECT: Fermi 425667201: optical counterpart search DATE: 14/06/30 17:45:25 GMT FROM: Leo Singer at CIT/PTF L. P. Singer (Caltech), M. M. Kasliwal (Carnegie Observatories/Princeton), V. B. Bhalerao (IUCAA), S. B. Cenko (NASA/GSFC), Y. Cao (Caltech), G. Duggan (Caltech), D. A. Perley (Caltech), and J. Johansson (Stockholm University) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: Fermi GBM reported trigger 425667201 at 2014-06-28 16:53:18.98 UT. Starting 2014-06-29 09:17:13 UT (JD 2456837.88696, 16.4 hours after the trigger), we began our search for optical counterparts using the Palomar 48-inch Oschin telescope (P48). Based on the final Fermi GBM localization, we selected 10 fields covering an area of 76 deg^2, with a 20% chance of containing the true location of the source. Sifting through candidate transient sources using image subtraction and standard intermediate Palomar Transient Factory vetting procedures, we detected several optical transients, of which we list five below. iPTF14deq, at r = 19.74 +/- 0.05 mag, at the coordinates: RA(J2000) = 23h 49m 29.57s (357.373189 deg) Dec(J2000) = +30d 47' 50.4" (+30.797328 deg) iPTF14det, at r = 17.62 +/- 0.01 mag, at the coordinates: RA(J2000) = 23h 29m 53.05s (352.471034 deg) Dec(J2000) = +29d 12' 12.3" (+29.203413 deg) iPTF14dev, at r = 19.13 +/- 0.03, at the coordinates: RA(J2000) = 23h 44m 29.96s (356.124852 deg) Dec(J2000) = +27d 04' 26.2" (+27.073938 deg) iPTF14dfc, at r = 20.58 +/- 0.09 mag, at the coordinates: RA(J2000) = 23h 39m 53.79s (354.974131 deg) Dec(J2000) = +35d 23' 43.3" (+35.395371 deg) iPTF14dfd, at r = 20.24 +/- 0.07 and rising, at the coordinates: RA(J2000) = 23h 55m 11.06s (358.796090 deg) Dec(J2000) = +27d 05' 21.2" (+27.089213 deg) The first four (iPTF14deq, iPTF14det, iPTF14dev, iPTF14dfc) showed no significant optical evolution over the course of an hour, nonetheless consistent (within the uncertainty in our photometry) with a fading of ~0.08 mag per hour for a typical optical afterglow (assuming a decay index alpha ~ -1). The last, iPTF14dfd, brightened by 0.65 +/- 0.01 mag over the course of half an hour. The first four had plausible nearby host galaxies in SDSS, but none had known redshifts. However, the candidates listed above had host galaxies with photometric redshifts that were compatible with the absolute magnitudes of typical long GRB afterglows, M_B >~ -20 (see Kann et al. 2011, http://dx.doi.org/10.1088/0004-637X/734/2/96). We obtained spectra of these five candidates with the Low Resolution Imaging Spectrometer (LRIS) mounted on the 10-m Keck I telescope. None of the spectra are consistent with an optical afterglow. We interpret iPTF14deq as an SN II at z=0.083 due to a blue continuum and weak Ha emission lines with a low-velocity P-cygni profile. We classify iPTF14det as an SN II-p at z=0.0197 due to broad Ha emission with a pronounced P-cygni profile. iPTF14dev is a type Ia supernova at a redshift of z=0.0655 with a spectrum consistent with a phase of about 6 days before maximum light. iPTF14dfc is a type I (probably, type Ia or Ic) supernova. Based on fitting the SN features with SNID (Stephane & Tonry 2007, http://dx.doi.org/10.1086/520494), we tentatively suggest a redshift of z=0.25. In iPTF14dfd, we find double-peaked Ha emission lines and He II 4686 at a redshift of z=0, superimposed on a blue continuum. Combined with its rapid brightening and lack of an associated galaxy, it is likely a CV outburst. The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi425667201.pdf shows the locations of the optical transients and the 10 P48 fields in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours. We thank the Fermi-GBM team for promptly sharing their detailed localizations with us. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16530 SUBJECT: SGR 1935+2154: Swift-BAT observations of additional short soft events DATE: 14/07/06 18:47:13 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummmings reports on behalf of the Swift-BAT team: Swift-BAT has observed three additional short, soft events from SGR 1935+2154 (Stamatikos et al. GCN 16520, Lien et al. GCN 16522). The first was at 285.8 seconds after the discovery event reported in Stamatikos et al. The second was at T+497.4 seconds. The third was at T+27157 seconds (BAT trigger # 603514; no automated response occurred since the brightness was less than the threshold set for retriggering on the known source). At the time of the earlier two events, Swift had slewed to the source position, so the source was on axis. At the time of the later event, the source was 17% coded in BAT. The fluences of the earlier events were about 1/3 and 1/5 of the fluence of the discovery event and were too low to get reliable spectral data. A simple power-law fit of the spectrum of the later event has a photon index of 2.8 ± 0.2. The fluence from 15-150 keV in 0.07 seconds was (6.1 ± 1.2) x 10^-8 ergs/cm^2. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16535 SUBJECT: Pre-discovery observations of SGR 1935+2154 in Swift archival data DATE: 14/07/07 13:45:22 GMT FROM: Sergio Campana at INAF-OAB S. Campana (INAF-Brera), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C. C. Thoene (IAA-CSIC), J. Gorosabel (IAA-CSIC/UPV-EHU), N. Rea (CSIC-ICE Barcelona) , F. Coti Zelati (Universita` dell'Insubria, INAF-Brera) Swift/XRT observed the new magnetar SGR 1935+2154 (Stamatikos et al. GCN 16520) twice before the activation of the source during the monitoring of the Galactic plane. The first observation took place on Dec 30, 2010 for 519 s (obsid 00045278001). SGR 1935+2154 is far off-axis and it is barely detected at a rate of 5.4E-03 ± 3.9E-03 cts/s (using sosta within XIMAGE at the enhanced Swift XRT position, Osborne et al. GCN 16521). The second observation took place on Aug 28, 2011 for 623 s (obsid 00045271001). SGR 1935+2154 is detected at a rate 1.55E-02 ± 0.63E-02 cts/s at RA(J2000)= 19h34m55.75s Dec(J2000)= 21:53:49.15 with an error radius of 8.6 arcsec. This position lies at 1.4 arcsec from the enhanced Swift position. If the source was in quiescence at that time, the outburst showed only an increase of the persistent flux of a factor of a few. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16545 SUBJECT: Fermi GBM trigger 140708682 is not a GRB DATE: 14/07/08 18:09:53 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 140708682 at 16:22:21 UT on 8 July 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16577 SUBJECT: Fermi GBM Observations of SGR 1935+2154 DATE: 14/07/11 10:30:04 GMT FROM: Yuki Kaneko at Sabanci U Y. Kaneko, E. Gogus (Sabanci University), G. Younes (USRA/NASA-MSFC), S. Guiriec (GSFC/CRESST/UMD), C. Kouveliotou (NASA-MSFC)(Sabanci University), A. von Kienlin (MPE) report on behalf of the Fermi GBM magnetar team: We have searched for untriggered events from the newly discovered SGR 1935+2154 using the daily GBM data of 6 days, from July 3 to July 8. We identified 3 bursts from the direction of the SGR at the following times coinciding with the Swift BAT observations (Cummings, GCN 16530), all on July 5: 1: 09:32:49 UT (426245572 Fermi MET = BAT trigger 603488) 2: 09:37:35 UT (426245857 Fermi MET = Trig+285.8 s) 3: 09:41:07 UT (426246069 Fermi MET = Trig+497.4 s) We note that the 3rd burst was extremely weak, detected with much lower significance (<3.5 sigma). The SGR was not visible to GBM at the time of the fourth event detected with BAT at Trig+27157 s (426272729 MET). No other events from the direction of the SGR were identified in the GBM data at >4.5-sigma level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16580 SUBJECT: Swift Trigger 604111 is not a GRB DATE: 14/07/12 03:18:33 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), J. A. Kennea (PSU), V. Mangano (PSU) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 02:58:30 UT, the Swift Burst Alert Telescope (BAT) triggered on a noise fluctuation on the rising background while entering the SAA. The XRT began observing the field at 03:00:00.6 UT, 89.9 seconds after the BAT trigger and centroided on a cosmic ray hit. Because this is a marginal significance BAT image peak, as Swift was entering the SAA, and there is no corresponding source at the correct location in XRT, we believe that this is not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16594 SUBJECT: Swift detection of UX Ari DATE: 14/07/15 21:42:34 GMT FROM: David Palmer at LANL W. H. Baumgartner (GSFC/UMBC), L. M. Z. Hagen (PSU), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), C. Pagani (U Leicester) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 21:14:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located the RS CVn star UX Ari (trigger=604675). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 51.649, +28.717 which is RA(J2000) = 03h 26m 36s Dec(J2000) = +28d 43' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers, there is no obvious variation in the light curve. Because BAT triggered on the first 5-minute image of a pointing, it is likely that the source was already in outburst at the nominal trigger time. The XRT began observing the field at 21:20:38.6 UT, 386.9 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 51.6474, 28.7144 which is equivalent to: RA(J2000) = +03h 26m 35.38s Dec(J2000) = +28d 42' 51.8" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 10 arcseconds from the BAT onboard position, within the BAT error circle. This position is consistent with UX Ari, also designated as 3XMM J032635.3+284254 in the XMM-NEWTON XMMSSC catalogue. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 7.65e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the U filter starting 862 seconds after the BAT trigger. UVOT detects a very bright source consistent with the position of UX Ari. Because of dead time effects, more analysis is required to estimate a position or the magnitude. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16597 SUBJECT: Swift observations of a flare from UX Ari DATE: 14/07/16 20:44:36 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA), S. A. Drake (CRESST/GSFC/USRA), L. M. Z. Hagen (PSU), P. Kuin (UCL/MSSL), R. Osten (STScI), C. Pagani (U Leicester), D. M. Palmer (LANL) The Swift team reports on its observations of a flare from the RS CVn star UX Ari. This source triggered the Swift/BAT onboard (Baumgartner, et al., GCN Circ. 16594) and observations were carried out by all Swift instruments. The trigger time was 21:14:11 UT on 15 July 2014. For the BAT, using the event data set from T-239 to T+963 sec from the recent telemetry downlink, the time-averaged spectrum from T+0 to T+320 sec (with some short data gaps) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.94 +- 0.38. The fluence in the 15-150 keV band is 7.2 +- 1.4 x 10^-7 erg/cm2. All the quoted errors are at the 90% confidence level. The BAT mask weighted light curve shows a flat peak from T-40, when the source came into the BAT field of view, until T+963, at the end of the event data. The source was already in outburst when the observations started. Data from the Swift/BAT transient monitor show activity from the source beginning at 15 July 2014, 19:38:37 UT (96 minutes before the trigger) and continuing until 16 July 2014, 00:48:37 UT. There was no detection in an observation starting at starting at 01:58 UT on July 16. The peak rate in the monitor (15-50 keV) is 0.03 ± 0.004 ct/s/cm^2 (~135 mCrab). The XRT observations consist of a total of 6.0 ks of Windowed Timing mode data. The XRT light curve can be modeled with a broken power-law, with an initial shallow decay with index alpha1 = 0.06 (+/-0.02) followed by a steeper decay after a break at T0+4.3 ks with an index alpha1 = 0.92 (+/-0.01) The XRT spectrum can be fitted with an absorbed two APEC model, with temperatures kT1 = 1.66 (+0.04, -0.05) keV and kT2 = 7.84 (+/-0.20) keV and a best-fitting absorption column of 3.8 (+/-0.1) x 10^20 cm^-2. The observed (unabsorbed) 0.3-10 keV flux is 4.37 x 10^-9 (4.51 x 10^-9) erg cm^-2 s^-1. The temperatures are consistent with what is expected for a large flare from this type of source. The column density to UX Ari (based on EUVE and other soft X-ray observations) is typically a few times 10^18 cm^-2, so the column derived from the flare spectrum, if real, would imply a major associated coronal mass ejection. UX Ari is too bright for UVOT aperture photometry, and during the flare initially exceeded the brightness limits for using UVOT readout streak photometry (Page et al, 2013, MNRAS Vol. 436, p. 1684.). The lower limits to the flare brightness exceeded uvw2 < 8.80, uvm2 < 8.27, uvw1 < 8.86. On 2014-07-15 at 22:50 UT the uvm2 magnitude had faded within the observable range, with uvm2=8.46+/-0.13, while on 2014-07-16 at 1:43UT the magnitude was uvm2=9.64+/-0.24. We note that the recent flare was also detected by MAXI (Kawagoe et al., ATel #6315). This source has been detected several times earlier in the BAT as reported by Krimm et al. (ATel #5907), the most recent being in mid-February 2014. The only other on board trigger was on 7 January 2012, reaching a peak of 0.013 ± 0.002 ct/s/cm^2 (~60 mCrab). We note that this Notice has also been posted as ATel #6319. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16632 SUBJECT: Trigger 607399: Swift detection of SGR1806-20 DATE: 14/07/29 02:51:50 GMT FROM: David Palmer at LANL M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 02:41:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Soft Gamma Repeater SGR 1806-20 (trigger=607399). Swift slewed immediately to the burst location. The BAT on-board calculated location is RA, Dec 272.172, -20.437 which is RA(J2000) = 18h 08m 41s Dec(J2000) = -20d 26' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty), which is 1.8 arcminutes from the location of the SGR. The BAT light curve showed a single-peaked structure with a duration of about 0.25 sec. The peak count rate was ~15000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 02:42:52.6 UT, 88.9 seconds after the BAT trigger. No source was detected in 303 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 93 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16635 SUBJECT: Correction to Fermi-LAT GCN Circular 16633 DATE: 14/07/29 16:29:24 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (University & INFN Trieste) and M. Arimoto (Tokyo Tech) report on behalf of the Fermi-LAT team: The number of LAT-detected photons reported in GCN 16633 is incorrect. There are only about 20 photons above 100 MeV and 4 photons above 1 GeV within 550 s. We apologize for the mistake. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16639 SUBJECT: Swift Trigger 607506 is probably noise DATE: 14/07/29 20:24:09 GMT FROM: David Palmer at LANL W. H. Baumgartner (GSFC/UMBC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 19:54:27.67 UT, the Swift Burst Alert Telescope (BAT) found a low-significance peak in an untriggered image at a location near NGC3109 (trigger=607506). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 150.766d, -26.028d which is RA(J2000) = 10h 03m 04s Dec(J2000) = -26d 01' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT lightcurve shows a rapidly increasing count rate, consistent with Swift's entry into the SAA. The XRT began observing the field at 19:57:03.3 UT, 155.6 seconds after the BAT trigger. No source was detected in 37 s of promptly downlinked data, which covered 94% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 118 seconds with the White filter starting 159 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. When BAT finds a marginal significance image peak in the vicinity of a nearby galaxy, as in this case, Swift makes follow-up observations with the narrow-field instruments to test the reality of the event. The expectation is that most such events will be noise. Due to the lack of a rate trigger, the marginal significance of the image peak (5.92 sigma), and the lack of a detection in the narrow field instruments, we do not believe that this is an astrophysical source. A final determination will require the full downlinked dataset. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16649 SUBJECT: Swift Trigger 607945: possible noise event in the direction of NGC2559 DATE: 14/08/01 12:36:41 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), L. M. Z. Hagen (PSU), A. Melandri (INAF-OAB) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 12:02:51 UT, the Swift Burst Alert Telescope (BAT) triggered on a location near NGC 2559 (trigger=607945). Swift did not slew because of Sun constraint. The BAT on-board calculated location is RA, Dec 124.350, -27.332 which is RA(J2000) = 08h 17m 24s Dec(J2000) = -27d 19' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers, there is nothing to be seen in the real-time TDRSS lightcurve. Further, this is a sub-threshold trigger (because of the spatial coincidence with the galaxy in the on-board catalog) and as such of low confidence. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 05:34 UT on 2014 August 22. There will thus be no XRT or UVOT data for this trigger before this time. This was a low significance BAT trigger in the direction of NGC 2559. Since the field is Sun constrained there will be no XRT or UVOT data to further ascertain the nature of the trigger, which is likely the result of a noise fluctuation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16677 SUBJECT: Swift trigger 609139 is probably 4U 1850-03 DATE: 14/08/10 14:50:34 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), D. Malesani (DARK/NBI), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 13:42:11 UT, the Swift Burst Alert Telescope (BAT) triggered and probably located 4U 1850-03 (trigger=609139). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 282.080, -2.444, which is RA(J2000) = 18h 48m 19s Dec(J2000) = -02d 26' 37" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Given that this is a 21-min image trigger (8.11 sigma), the information in the BAT ring buffer has been wrapped, so there is no real-time TDRSS light curve available. The XRT began observing the field at 14:08:41.9 UT, 1590.3 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 282.07027, -2.42364 which is equivalent to: RA(J2000) = 18h 48m 16.86s Dec(J2000) = -02d 25' 25.1" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 81 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 5.5 arcseconds from a known X-ray source: 1SXPS J184816.5-022522. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 2.97 x 10^-3 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ184816.5-022522 for details of these previous observations. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 1593 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The above positions appear to be consistent with the known high mass X-ray binary 4U 1850-03, and we believe the BAT trigger indicates activity from this known source. The identifier 1SXPSJ184816.5-022522, derived from the Swift XRT point source survey, is most consistent with the current Swift XRT localization, but it is possible this source is the same as the 4U 1850-03. However, as this is a location 0.4 deg from the Galactic Plane, we cannot rule out the possibility of a distinct Galactic source, nearby to 4U 1850-03. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16685 SUBJECT: Swift Mission Operations Center Moving DATE: 14/08/12 18:19:27 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT Jamie A. Kennea (PSU) on behalf of the Swift Mission Operations Center reports: The Swift Mission Operations Center (MOC), located near the Penn State University Park campus, is planning to move to a new office building on Tuesday August 26th starting at 8:00am Eastern Time (12:00 UT). This move is expected to take no more than 72 hours to complete. In the week leading up to the move (from Tuesday August 19th), the Swift schedulers will be creating science plans with a longer lead time than usual. This will affect our ability to schedule TOO requests into the observing plan at the last minute, so we ask that requesters consider this when submitting TOOs during this period and submit earlier if possible. During the move itself, we will not accept any new TOO requests, Swift will not perform automated XRT/UVOT observations of BAT triggers (we will continue to distribute BAT GRB detections through GCN), and the Penn State Swift website will be offline. A program of pre-planned observations will be performed by Swift during the period of the move, so science data will continue to be collected. However, until the MOC is operational, data taken during this period will not be delivered to the Swift Science Data Center, so there will be a delay in being able to obtain the processed data products from these observations. At the end of the 72 hour period, we expect all Swift capabilities to be fully restored. However, it is likely that some capabilities will return sooner than that. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16692 SUBJECT: Swift Trigger 609694 is probably not an astrophysical source DATE: 14/08/16 18:50:38 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 18:34:11 UT, the Swift Burst Alert Telescope (BAT) located a marginal significance (5.84 sigma) image peak in the vicinity of the known source IGR J16185-5928 (trigger=609694) in an untriggered image. Swift slewed immediately to the location in order to confirm or refute the event. The BAT on-board calculated location is RA, Dec 244.998, -59.389 which is RA(J2000) = 16h 19m 59s Dec(J2000) = -59d 23' 21" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for images without a corresponding rate trigger, no obvious variation is visible in the BAT rates lightcurve. The XRT began observing the field at 18:36:33.1 UT, 141.5 seconds after the BAT trigger. No source was detected in 443 s of promptly downlinked data, which covered 93% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 144 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 53% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.26. Due to the marginal significance of the detection (5.84 sigma), the lack of a corresponding rate trigger, the large distance of the image peak from the known source (12 arcminutes), and the lack of a corresponding source in the XRT and UVOT instruments, we believe that this is a statistical fluctuation in image space rather than an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16707 SUBJECT: Swift detection of SAX J1712.6-3739 DATE: 14/08/18 17:58:29 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 17:10:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source consistent with the position of SAX J1712.6-3739 (trigger=609878). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 258.161, -37.657 which is RA(J2000) = 17h 12m 39s Dec(J2000) = -37d 39' 22" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a ~10-second peak at ~T+130. This was a 332-second image trigger. BAT retriggered on the same source with the next 320-second image trigger attempt (trigger=609879), with a higher flux. The lightcurve shows rapid fluctuations. The peak count rate was ~200 counts/sec (15-350 keV), at 130 sec after the trigger. The XRT began observing the field at 17:16:59.4 UT, 415.8 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 258.1547, -37.6444 which is equivalent to: RA(J2000) = +17h 12m 37.13s Dec(J2000) = -37d 38' 39.8" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 48 arcseconds from the BAT onboard position, within the BAT error circle. This is 4.5 arcseconds away from the position of SAX J1712.6-3739 (Wiersema et al. 2009, MNRAS 397, 6). This source is in the Swift XRT 1SXPS catalogue as 1SXPS J171236.9-373842 with a mean 0.3-10 keV count-rate of 3.830 +/- 0.033 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ171236.9-373842 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.69e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 425 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. We note that this is a crowded field with large expected extinction. No correction has been made for the large, but uncertain extinction expected. This source has been detected by BAT many times, with the most recent on-board detection in 2014 May, and it is variable but persistently visible in BAT ground analysis. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16720 SUBJECT: Fermi trigg_num 430148973: bright OT inside large error box! DATE: 14/08/19 16:07:13 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Denisenko, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB140819.58 27 sec after notice time and 58 sec after trigger time at 2014-08-19 13:50:28 UT. On our first (10s exposure) set we found 1 optical transient within FERMI error-box (ra=16 44 07 dec=-10 58 00 r=35.270000) : RA DEC 16h 45m 20.22s -10d 06m 43.0s m (unfiltered) = 10.4 FWHM = 2.034 The discovery image is available at http://observ.pereplet.ru/images/GRB140819.58.jpg The 5-sigma upper limit has been about 12.6 mag There is no OT on the next images! The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16722 SUBJECT: Fermi trigg_num 430148973: OSN I-band observations DATE: 14/08/19 21:21:44 GMT FROM: Javier Gorosabel at IAA-CSIC F. Espartero (IAA-CSIC), F.J. Aceituno (OSN/IAA-CSIC), J. Gorosabel (IAA-CSIC/UPV-EHU) and A.J. Castro-Tirado (IAA-CSIC/UMA), report on behalf of a larger collaboration: We observed the field of the optical candidate reported for Fermi trigger #430148973 (Lipunov et al. GCN 16720) with the 1.5m OSN telescope at Observatorio de Sierra Nevada (Spain). The observations were carried out in the I-band starting at 20:27:42 UT (6.6 hours post trigger). We do not detect any source brighter than I=20.2 (Vega) consistent with the candidate position. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16723 SUBJECT: Fermi 430148973/MASTER candidate: LCO-Sutherland observations DATE: 14/08/19 22:23:05 GMT FROM: Simone Dichiara at Ferrara U/Italy S. Dichiara, C. Guidorzi (U. Ferrara), D. Kopac (U. Ljubljana) on behalf of a large collaboration report: We observed the MASTER OT candidate (Lipunov et al. GCN Circ 16720; Espartero et al. GCN Circ. 16722) with one of the Las Cumbres Observatory 1-m telescopes in Sutherland (South Africa) on August 19 at 17:43:02 UT, i.e. ~3.9 hours after the trigger time (GCN Circ. 16720) with the r',i',z', and Y filters. At the position of the MASTER OT candidate we found nothing down to the following limits: Mid time from Total Exp Filter Magnitude trigger (hr) (s) ------------------------------------------------- 4.51 1080 r' > 20.4 4.57 960 i' > 19.6 ------------------------------------------------- calibrated against nearby USNOB1 stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16727 SUBJECT: Fermi trigger 430148973: Swift-XRT observation DATE: 14/08/20 13:39:55 GMT FROM: Ben Gompertz at U.of Leicester B.P Gompertz and K.L. Page (U. Leicester) report on behalf of the Swift-XRT team: We report on Swift-XRT observations of the field of the optical transient observed by MASTER II (Lipunov et al. GCN Circ 16720) in the error circle of the Fermi GBM discovered possible GRB (trigger number 430148973), 38.9 ks after trigger. In 5 ks of observations, no source is detected consistent with the MASTER position to a 3-sigma upper limit of 1.7E-3 cts/s. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16730 SUBJECT: Fermi GBM Trigger 140819576/ 430148973/ MASTER OT DATE: 14/08/20 23:24:47 GMT FROM: Valerie Connaughton at UAH/NSSTC Valerie Connaughton (UAH) reports for the GBM team: "At 13:49:30.04 UT on 19 August 2014, Fermi GBM triggered on an event that was classified by the Flight Software as having an unreliable location and that was determined by the automated Ground software to be inconsistent with an astrophysical source location. The preliminary classification of this event was an accidental trigger. The complete data set has since been analyzed and we find no reason to revise this classification. It is possible based on the count rates in two detectors (NaI 1 and 6) that there is a very weak, short GRB in the 64 ms before the trigger time, but there is no obvious signal in other detectors. Based on the geometry of the GBM detectors to the MASTER OT position (Lipunov et al., GCN 16720), we would expect to see significant signal in other NaI detectors. We conclude that the GBM trigger is unrelated to the OT detected by MASTER and is most likely an accidental trigger. There is a small possibility that the trigger is a very weak short GRB from an undetermined location, probably at very large angle to the spacecraft z-axis. Recommendations to observers: observations using GBM Flight Software positions from triggers with classifications other than GRB, particularly those very large reported errors, have low probabilities of success. Triggers classified as GRBs by the Flight Software will have an automated Ground position distributed in a socket connection or GCN notice within seconds. These ground localizations are more accurate, and are always distributed unless the ground software classifies the localization as unreliable." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16740 SUBJECT: Fermi TRIGGER_NUM 430583595: MASTER OT JR011101.13+603337.5 detection DATE: 14/08/25 09:05:02 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, V. Lipunov, E. Gorbovskoy, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Denisenko, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was starting survey on the FERMI GRB140824.61 error-box (ra=01 13 19 dec=+58 38 24 r=1.490000) 7913 sec after notice time and 9534 sec after trigger time at 2014-08-24 17:12:06 UT. The 5-sigma upper limit on our first (180s exposure) set is about 19.1 mag (unfiltered) MASTER-Tunka auto-detection system discovered MASTER OT JR011101.13+603337.5 source at: (RA, Dec) = 01h 11m 01.13s +60d 33m 37.5s on 2014-08-24.71962 UT. The OT unfiltered magnitude is 17.0m (limit 19.5m). The OT is seen in 16 images. There is no minor planet at this place. We have reference image without OT on 2013-06-18.75418 UT with unfiltered magnitude limit 19.1m. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/011101.13603337.5.png The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16741 SUBJECT: Fermi TRIGGER_NUM 430583595: MASTER OT 20 hours later DATE: 14/08/25 14:10:25 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, V. Lipunov, E. Gorbovskoy, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Denisenko, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) The second epoch observation of the MASTER OT J011101.13+603337.5 (GCN Cirs., 16740) was obtained by MASTER-Tunka at 2014-08-25 13:32:21 (~20 hours after first observations). The transient MASTER OT J011101.13+603337.5 slightly fell to 17.5 mag (unfiltered). 0.5 mag is very slow for GRB afterglow and CV nature of the OT is more plausible. Follow up spectral observations are required. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16744 SUBJECT: Swift Mission Operations Center Moving Tomorrow DATE: 14/08/25 19:44:23 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT Jamie A. Kennea on behalf of the Swift Mission Operations Center reports: The Swift Mission Operations Center (MOC), located near the Penn State University Park campus, is will move to a new office building on Tuesday August 26th starting at 8:00am Eastern Time (12:00 UT). This move is planned to be fully completed within 72 hours. During the move, we will not accept any new TOO requests and Swift will not perform automated observations of any BAT triggers (GRBs, transients, etc.). A program of pre-planned observations will be performed by Swift during the period of the move, so science data will continue to be collected. However, until the MOC is operational, data taken during this period will not be delivered to the Swift Science Data Center, so there will be a delay in being able to obtain the processed data products from these observations. At the end of the planned 72 hour move period, we expect all Swift capabilities to be fully restored. However, it is likely that most capabilities will return sooner than that. We will issue further notices to update on progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16745 SUBJECT: Fermi TRIGGER_NUM 430645968: MASTER OT inside error box DATE: 14/08/26 10:44:45 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, E. Gorbovskoy, V. Lipunov, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Denisenko, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was starting survey on the FERMI GRB140825.33 error-box (ra=22 51 21 dec=+31 05 24 r=2.660000) 19218 sec after notice time and 23046 sec after trigger time at 2014-08-25 14:16:52 UT. The 5-sigma upper limit on our first (180s exposure) set is about 18.73mag MASTER II robotic telescope located in Kislovodsk was starting survey on the FERMI GRB140825.33 error-box (ra=22 51 21 dec=+31 05 24 r=2.660000) 29715 sec after notice time and 33543 sec after trigger time at 2014-08-25 17:11:49 UT. The 5-sigma upper limit on our first (180s exposure) set is about 18.86mag MASTER-Tunka auto-detection system discovered MASTER OT J230448.20+324534.1 at (RA, Dec) = 23h 04m 48.20s +32d 45m 34.1s on 2014-08-25.62245 UT. The OT unfiltered magnitude is 18.6m (limit 19.9m). The OT is seen in 2 images. There is no minor planet at this place. THere is SDSS9 J230447.99+324540.9 galaxy (Rmag = 22) with 7.3 arcsec offset. We have reference image without OT on 2013-08-30.62251 UT with unfiltered magnitude limit 19.9m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/230448.20+324534.1.png The coverage map and OT position are available at http://master.sai.msu.ru/static/GRB140825.png The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16749 SUBJECT: Swift Burst Response Reenabled DATE: 14/08/27 15:41:34 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea reports on behalf of the Swift Mission Operations Center: At 14:40UT on April 27, 2014, Swift's automated slewing was re-enabled. This means that if BAT triggers on a new GRB, Swift will slew (if possible) to collect data with the XRT and UVOT instruments, returning Swift to full science functionality. Currently, the Swift Mission Operation Center move is still in progress and we are not accepting any new TOO requests, although we expect to end the TOO moratorium tomorrow. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16753 SUBJECT: Swift Mission Operations Center Fully Operational DATE: 14/08/28 18:49:49 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT Jamie A. Kennea (PSU) reports on behalf of the Swift Mission Operations Center: The Swift Mission Operations Center (MOC), located near the Penn State University Park campus, is back to full operational status. As of 14:40UT August 28th, 2014, Swift's automated burst slew response was re-enabled (see GCN #16749), and as of 18:30UT, August 29th, 2014, we have lifted the moratorium on TOOs. We thank Swift's user community for their patience during the move. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16817 SUBJECT: Fermi GBM trigger 140913075 is not a GRB DATE: 14/09/13 04:19:23 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 432265650 / 140913075 at 01:47:27.42 UT on 13 September 2014, tentatively classified as a burst from SGR1806n20 or as a GRB (2nd most likely), is in fact due to neither of these. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16829 SUBJECT: Swift detection of outburst from 4U 1700+24 DATE: 14/09/17 14:11:04 GMT FROM: David Palmer at LANL D. N. Burrows (PSU), S. B. Cenko (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (PSU), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), C. Pagani (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), C. A. Swenson (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team: At 13:30:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located the symbiotic star 4U 1700+24 (trigger=612974). Swift slewed immediately to the source location. The BAT on-board calculated location is RA, Dec 256.633, +23.950 which is RA(J2000) = 17h 06m 32s Dec(J2000) = +23d 57' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Because this is a 15 minute image trigger, the BAT lightcurve is not immediately available. The XRT began observing the field at 13:50:12.7 UT, 1177.2 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 256.6459, 23.9711 which is equivalent to: RA(J2000) = +17h 06m 35.02s Dec(J2000) = +23d 58' 16.0" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 87 arcseconds from the BAT onboard position, within the BAT error circle. This position is 6.4 arcseconds from a known X-ray source: 1SXPS J170634.5+235816, and 7.3 arc-seconds from the optical position of V934 Her, thought to be the optical counterpart of 4U 1700+24. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.3810 +/- 0.0067 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ170634.5%2B235816 for details of these previous observations. The initial flux in the 2.5 s image was 1.79e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 64 seconds with the White filter starting 1185 seconds after the BAT trigger. The only source within the XRT error circle is the known bright (V=7.6) optical source V934 Her. The source 4U 1700+24 has been rising in brightness in the Swift/BAT hard X-ray transient monitor since 12 September 2014. It is currently seen in the one-day average for 17 September at 0.011 +/- 0.004 ct/s/cm^2 (~50 mCrab; 15-50 keV). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16840 SUBJECT: Swift Trigger 613516 is not an astrophysical event DATE: 14/09/24 01:47:19 GMT FROM: David Palmer at LANL M. M. Chester (PSU) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 01:39:55 UT, a temporary loss of star tracker lock caused the misidentification of Vela X-1 as an unknown source (trigger 613516). This event is not astrophysically significant. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16841 SUBJECT: Swift Trigger 613581 is not an astrophysical event DATE: 14/09/24 19:18:13 GMT FROM: David Palmer at LANL D. M. Palmer (LANL) report on behalf of the Swift Team: Swift Trigger 613581 is a consequence of the previous misidentification of Vela X-1 (Palmer et al. GCN #16840). It does not correspond to an astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16874 SUBJECT: Swift possible detection of the Be star HD 305560 DATE: 14/10/02 05:17:13 GMT FROM: David Palmer at LANL M. De Pasquale (INAF-IASFPA), N. Gehrels (NASA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 04:44:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source consistent with the position of the Be star HD 305560 (trigger=614193). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 161.614, -60.581 which is RA(J2000) = 10h 46m 27s Dec(J2000) = -60d 34' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT lightcurve shows variation due to Vela X-1, which is also in the BAT FOV, but no other obvious variation that can be attributed to the new source, as is usual for an image trigger. The trigger time corresponds to the start of the observation, so the source may have been active before it came into the BAT field of view. The XRT began observing the field at 04:51:41.0 UT, 417.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 161.61728, -60.56433 which is equivalent to: RA(J2000) = 10h 46m 28.15s Dec(J2000) = -60d 33' 51.6" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 60 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.42 x 10^22 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 1.36e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the U filter starting 873 seconds after the BAT trigger. The X-ray source is spatially coincident with HD 305560, which is saturated in the UVOT image, consistent with its listed U magnitude of 9.5. Further analysis will be needed to determine if there is any variation in the optical flux. No new optical source is seen in the 2.7'x2.7' sub-image. The typical 3-sigma upper limit has been about 19.2 mag. Although high energy emission has not been previously detected from HD 305560, its status as a bright Be star in close coincidence with the XRT location leads us to believe that this star is the detected source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16877 SUBJECT: Swift observations of HD 305560 DATE: 14/10/02 19:55:27 GMT FROM: Kim Page at U.of Leicester A. Maselli (INAF-IASFPA), K. L. Page (U. Leicester), H. A. Krimm (CRESST/GSFC/USRA) and S. R. Oates (IAA-CSIC, MSSL-UCL) report on behalf of the Swift team: At 04:44:43 on 2014 October 02, the Swift Burst Alert Telescope (BAT) triggered on what appears to be the Be star HD 305560 (GCN Circ. #16874). Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of the BAT data. The BAT ground-calculated position is RA, Dec = 161.562, -60.604 which is equivalent to RA(J2000) = 10h 46m 15.0s Dec(J2000) = -60d 36' 13.9" with an uncertainty of 3.1 arcmin (radius, sys+stat, 90% containment). The partial coding was 53%. The mask-weighted light curve shows that the source entered the field of view during a slew at around T-100 seconds and that the count rate was relatively flat through the duration of the event data. In the 15-50 keV range, the count rate during this period averaged 0.04 +/- 0.005 ct/s/cm^2. Examination of the BAT transient monitor images before the trigger shows no detection in earlier intervals going back to 2014 September 01, the most recent observation ending 13 minutes before the trigger. Observations made after the burst response interval show the source fading rapidly in the BAT monitor 15-50 keV band. By 09:36:32.0 UT, the rate was down to 0.005 +/- 0.003 ct/s/cm^2 and by 10:49:28.0, the source had faded to a level consistent with background. This rapid fading is not consistent with the typical behaviour of a high-mass X-ray binary system in outburst. The time-averaged spectrum from T+0.00 to T+320.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.42 +/- 0.39. The fluence in the 15-150 keV band is 1.0 +/- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.1 +/- 0.0 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/614193/BA/ The Swift X-Ray Telescope (XRT) started observing HD 305560 at T0+424 s (where T0 corresponds to the time at which HD 305560 entered the BAT field of view). Using data from the whole available dataset we found a bright, uncatalogued X-ray source located at RA, Dec 161.6173, -60.5644 which is equivalent to RA(J2000) = 10h 46m 28.14s Dec(J2000) = -60d 33' 51.7" with an uncertainty of 3.6 arcseconds (radius, 90% confidence). This location is 2.9 arcmin from the BAT ground-calculated position, within the BAT error circle, and is 2.5 arcsec from the SIMBAD position of the Be star HD 305560. Initially, the soft X-ray 0.3-10 keV count rate was at the level of ~15 ct/s; then, after reaching a peak of 20 ct/s (corresponding to 1.8e-9 erg/cm^2/s, observed) at ~T0+540 s, it was followed by a moderate decay, reaching a count rate of ~6 ct/s by ~1.2 ks after the trigger. The second snapshot of XRT data started at T0+5.7 ks, with the soft X-ray emission showing a flaring phase, with the count rate rapidly rising from ~0.6 ct/s to ~18 ct/s at T0+6.4 ks and keeping at that count rate level until this snapshot concluded, at T0+6.9 ks. Data collected at T0+11.5 ks caught the source in an evident decaying phase with a count rate of ~7.6 ct/s down to 0.6 ct/s when the observation concluded, at T0+18.4 ks. The XRT data collected between T0+424 s and 18.4 ks can be fitted with a hard power-law (Gamma = 0.81 +0.07/-0.12) plus an optically thin thermal component (kT = 0.45 +/- 0.15 keV), with a high absorbing column of (3.4 +0.7/-0.4)x10^22 cm^-2. Time-slicing the XRT spectra provides no strong evidence for changes in these temperatures during this interval. Because of the brightness of the optical source (V~9.8 mag), the UV/Optical Telescope (UVOT) data are saturated in all 6 optical and UV filters and have therefore not been analysed in detail. This information has also been posted as ATel 6526. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16904 SUBJECT: Trigger 614903: Swift detection of IGR J17544-2619 DATE: 14/10/10 15:38:21 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), D. N. Burrows (PSU), P. D'Avanzo (INAF-OAB), D. Malesani (DARK/NBI), V. Mangano (PSU), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 15:04:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located a transient (trigger=614903). Swift slewed immediately to the transient. The BAT on-board calculated location is RA, Dec 268.607, -26.330 which is RA(J2000) = 17h 54m 26s Dec(J2000) = -26d 19' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger so details of the lightcurve can not yet be determined. The XRT began observing the field at 15:06:31.7 UT, 132.4 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 268.6054, -26.3282 which is equivalent to: RA(J2000) = +17h 54m 25.30s Dec(J2000) = -26d 19' 41.5" with an uncertainty of 5.8 arcseconds (radius, 90% containment). This location is 8.3 arcseconds from the BAT onboard position, within the BAT error circle. This position is 11.1 arcseconds from that of the Supergiant Fast X-ray Transient IGR J17544-2619, which is likely to be the transient that triggered the BAT. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 0.1 s image was 2.08e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 168 seconds with the U filter starting 138 seconds after the BAT trigger. The 2.7'x2.7' sub-image reveals the known optical counterpart at a U magnitude of 15.27 approximately 10.6" from the XRT source. No other source is detected to a typical 3-sigma upper limit of about 19.2 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16908 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 141014781 is not a GRB DATE: 14/10/14 20:21:50 GMT FROM: George A. Younes at USRA/NASA/MSFC George Younes (USRA/NASA-MSFC) report on behalf of the Fermi Gamma-ray Burst Monitor Team: “The Fermi Gamma-ray Burst Monitor (GBM) trigger 141014781 at 18:45:09.85 UT on 14 October 2014, which resulted in an Autonomous Repoint Request (ARR), tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16949 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 141025734 is not a GRB DATE: 14/10/25 20:01:30 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 435951381 / 141025734 at 17:36:18.76 UT on 25 October 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to an X1.0 solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16959 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 141026452 is not a GRB DATE: 14/10/26 13:35:15 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 436013492 / 141026452 at 10:51:29.92 UT on the 26th of October 2014, initially classified as a GRB, is in fact due to a X2.0 solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17032 SUBJECT: GRB DATE: 14/11/06 18:42:04 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), E. Mazaeva (IKI), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB GRB 141026Ð (Hagen et al., GCN 16950) with ZTSh telescope of CrAO observatory starting on Oct. 26 (UT) 18:25:48. We took several images in R-filter of 120 s exposure under poor weather conditions and mean seeing of 5". The optical afterglow (Littlejohns et al. GCN 16592; Varela et al. GCN 16953; Gorosabel et al. GCN 16954) is clearly visible in our stacked image. Photometry of a combined image is following Date UT start, t-t0 Filter Exp. OT OT_err (mid, days) (s) 2014-10-26 18:25:48 0.7020 R 53*120 21.88 0.18 The photometry is based on USNO-B1.0 stars RA DEC R 044,065509 +26,958050 18.71 044,051792 +26,894737 18.59 044,049131 +26,929059 17.48 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17050 SUBJECT: Swift Trigger 618134 is not an astrophysical event DATE: 14/11/10 03:54:09 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), D. M. Palmer (LANL) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 03:43:55 UT, the Swift Burst Alert Telescope (BAT) triggered while there was a star tracker loss of lock. It mistakenly identified Vela X-1 as a new source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17060 SUBJECT: Swift Trigger 618391 is not an astrophysical event DATE: 14/11/12 04:33:30 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 04:21:55, BAT made an image trigger while the Swift had lost star tracker lock. As a result, it mistakenly identified Sco X-1 as a new source. Due to a Sun constraint, Swift will not slew to the calculated position and current observations will not be affected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17061 SUBJECT: Swift Trigger 618402: probable noise event DATE: 14/11/12 10:14:17 GMT FROM: Craig Markwardt at NASA/GSFC M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), D. Malesani (DARK/NBI) and C. B. Markwardt (NASA/GSFC) report on behalf of the Swift Team: At 09:06:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located image trigger 618402. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 189.977, +15.479 which is RA(J2000) = 12h 39m 55s Dec(J2000) = +15d 28' 44" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve does not show any significant variation, which is typical for an image trigger. The on-board image significance is 6.3 sigma, which is below the threshold for declaring a burst. However, ground-based processing does find a slightly improved significance of 6.5 sigma. More information will be known after processing the full BAT data set. The XRT began observing the field at 09:08:42.0 UT, 134.8 seconds after the BAT trigger. No X-ray source was detected in 590 s of promptly-downlinked data, suggesting that the initial on-board centroid was likely due to a cosmic ray. UVOT took a finding chart exposure of 150 seconds with the White filter starting 142 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. Results from the list of sources generated on-board are not available at this time. This was a low-significance image trigger in the direction of NGC 4595. However, NGC 4595 is 11 arc minutes from the center of the BAT error circle (error circle radius 3 arcminutes), so the association is unlikely. Given the lack of detection of XRT or UVOT counterparts, this trigger is likely the result of a noise fluctuation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17068 SUBJECT: Trigger 618634: Swift detection of Vela X-1 DATE: 14/11/14 21:35:50 GMT FROM: Caryl Gronwall at PSU/Swift-UVOT S. D. Barthelmy (GSFC), M. M. Chester (PSU), C. Gronwall (PSU), T. Sakamoto (AGU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 21:11:12 UT, the Swift Burst Alert Telescope (BAT) triggered on Vela X-1 (trigger=618634). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 135.536, -40.534, which is RA(J2000) = 09h 02m 09s Dec(J2000) = -40d 32' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a cluster of peaks with a duration of about 40 sec. The peak count rate was ~500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 21:13:29.8 UT, 137.6 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 135.5254, -40.5558 which is equivalent to: RA(J2000) = +09h 02m 6.10s Dec(J2000) = -40d 33' 20.9" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 83 arcseconds from the BAT onboard position, within the BAT error circle. This position is 9.5 arc seconds from Vela X-1. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 7.20 +/- 0.21 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ090206.7-403318 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.88e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 143 seconds after the BAT trigger. The optical counterpart to Vela X-1 is readily detected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17069 SUBJECT: Swift Trigger 618673: probable noise event DATE: 14/11/15 09:40:13 GMT FROM: Caryl Gronwall at PSU/Swift-UVOT W. H. Baumgartner (GSFC/UMBC), M. De Pasquale (INAF-IASFPA), C. Gronwall (PSU), A. Maselli (INAF-IASFPA) and E. Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Swift Team: At 09:10:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located on trigger 618673. Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 233.024, +32.694 which is RA(J2000) = 15h 32m 06s Dec(J2000) = +32d 41' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed nothing of note for this low significance image trigger. The XRT began observing the field at 09:13:05.1 UT, 149.9 seconds after the BAT trigger. No source was detected in 859 s of promptly downlinked data, which covered 97% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 153 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. We believe this trigger to not be from an astrophysical source because of the low significance of the BAT source in the image domain and the lack of an XRT counterpart. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17173 SUBJECT: Swift detection of 4U 1700+24 (= V934 Her) DATE: 14/12/13 02:18:26 GMT FROM: David Palmer at LANL J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 01:56:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located the source 4U 1700+24 (trigger #621278). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 256.660, +24.020 which is RA(J2000) = 17h 06m 38s Dec(J2000) = +24d 01' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers, there is no obvious variation in the immediately available BAT lightcurve. The XRT began observing the field at 01:58:04.5 UT, 113.5 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 256.6412, 23.9734 which is equivalent to: RA(J2000) = +17h 06m 33.89s Dec(J2000) = +23d 58' 24.2" with an uncertainty of 5.3 arcseconds (radius, 90% containment). This location is 178 arcseconds from the BAT onboard position, within the BAT error circle. This position is 9.3 arcseconds from that of a known X-ray source: 4U 1700+24 (also known as V934 Her). No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.48e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 122 seconds after the BAT trigger. The 2.7'x2.7' sub-image only shows the bright (V=7.6) known source V934 Her. This symbiotic X-ray binary system was previously observed in outburst by Swift and has been active for roughly the past year (Krimm et al., ATel #6482). A BAT lightcurve of its activity is available at: http://swift.gsfc.nasa.gov/results/transients/weak/4U1700p24/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17195 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 440728127 / 141220020 is not a GRB DATE: 14/12/20 01:27:55 GMT FROM: Peter Jenke at MSFC P.Jenke (UAH) report on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 440728127 / 141220020 at 00:28:44.18 UT on the 20th of December 2014, initially classified as a GRB, is in fact due to a X2.0 solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17250 SUBJECT: Fermi GBM trigger 141229739 is not a GRB DATE: 14/12/29 21:19:35 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 441567881 / 141229739 at 17:44:38.22 UT on 29 December 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17267 SUBJECT: Short burst found in ground analysis of Swift-BAT data DATE: 15/01/02 23:43:01 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings reports on behalf of the Swift-BAT science team: A short burst occurred during a Swift slew at 15:23 on Jan 1, 2015. It triggered Fermi GBM, trigger number 441818617. A significant source was found in ground analysis of BAT slew data at RA, Dec 188.044, -10.956, which is RA (J2000) 12h 32m 10.5s Dec (J2000) -10d 57' 21" with an estimated 90% containment radius of 2.5 arcmin. The lightcurve shows a single peak with a T90 of 0.018 +- 0.006 seconds. There appears to be significant spectral lag. The spectrum seen in BAT is soft. The best fit function is a blackbody spectrum with kT = 9.6 +- 1.5 keV. A simple powerlaw fit has a photon index of 3.3 +- 0.5. The blackbody fit gives a fluence between 15-150 keV in 0.1 seconds of (2.3 +- 0.6) x 10^-8 ergs/cm^2. Errors are 90% confidence. A Swift TOO request has been submitted in order to determine the nature of the source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17268 SUBJECT: Swift J123205.1-105602: XRT and UVOT observations of soft short burst source DATE: 15/01/03 19:06:28 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings, M. Gropp (PSU), K. L. Page (U. Leicester), M. Siegel (PSU) We report on Swift followup observations of the source of the ground-detected short, soft burst reported on Jan 1, 2015 by Cummings (GCN Circ. 17267). We have analysed 3.3 ks of XRT data from 139.2 ks to 155.5 ks after the burst. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the BAT error circle. Using 2057 s of PC mode data and 3 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 188.02119, -10.93389 which is equivalent to: RA (J2000): 12h 32m 05.09s Dec(J2000): -10d 56' 02.0" with an uncertainty of 2.4 arcsec (radius, 90% confidence). This position is 111 arcsec from the BAT position. The source has a mean count rate of 1.4e-02 ct/sec; we cannot determine at the present time whether it is fading. The spectrum is not well-determined. However, the best fit results from the data collected so far are: Gamma = 2.5 ± 0.5, with no evidence for NH above the Galactic value of 3.5e20 cm^-2. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020464. There is an optical source in the DSS consistent with the XRT source. The source is detected in UVOT with a white magnitude of 18.44 +- 03. It shows no significant variability over the 15 ks spanned by the observations. A followup Swift TOO has been requested with the target number 20464, in order to observe any fading and to refine the spectrum. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17271 SUBJECT: Swift J123205.1-105602: Magellan candidate afterglow DATE: 15/01/03 21:44:34 GMT FROM: Wen-fai Fong at U of Arizona W. Fong (U. Arizona), B. J. Shappee (Carnegie) and E. Berger (Harvard) report: "We observed the location of the short-duration soft burst, Swift J123205.1-105602, detected by Fermi/GBM (Trigger no. 441818617) and Swift/BAT (Cummings; GCN 17267) with the Inamori Magellan Areal Camera and Spectrograph (IMACS) mounted on the Magellan/Baade 6.5-m telescope. We obtained 8x150-sec of r-band observations at a mid-time of 2015 Jan 03.297 UT (1.66 days post-burst) in 0.8" seeing at an airmass of 1.6. Within the XRT position (Cummings et al.; GCN 17268), we detect a faint point-like optical source located at RA(J2000) = 12:32:05.09 Dec(J2000) = -10:56:03.0 with an uncertainty of 1" in each coordinate (registered to 2MASS). We note that this candidate optical afterglow is situated ~3" southeast from the center of a bright catalogued galaxy 2MASX J12320498-1056010, also detected by Swift/UVOT (Cummings et al.; GCN 17268). Further observations are planned to determine the nature of this source." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17280 SUBJECT: Swift detection of 4U 1700+24 (= V* V934 Her) DATE: 15/01/04 16:08:43 GMT FROM: David Burrows at PSU/Swift D. N. Burrows (PSU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), M.E. Gropp (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 15:39:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located 4U 1700+24 (= V934 Her) (trigger=623434). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 256.627, +23.962 which is RA(J2000) = 17h 06m 30s Dec(J2000) = +23d 57' 45" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 15:45:46.6 UT, 399.7 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 256.6423, 23.9712 which is equivalent to: RA(J2000) = +17h 06m 34.15s Dec(J2000) = +23d 58' 16.3" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 60 arcseconds from the BAT onboard position, within the BAT error circle. This position is 5.5 arcseconds from a known X-ray source: 1SXPS J170634.5+235816, which is coincident with V* V934 Her. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.3810 +/- 0.0067 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ170634.5%2B235816 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.90e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 411 seconds after the BAT trigger. The 2.7'x2.7' sub-image only shows the bright (V=7.6) known source V* V934 Her. This symbiotic star has been seen by Swift multiple times in the past few months (e.g. Kennea et al., GCN 17173; Krimm et al. ATel 6482) in an escalating series of peaks. The BAT lightcurve can be seen at http://swift.gsfc.nasa.gov/results/transients/weak/4U1700p24/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17283 SUBJECT: Fermi GBM trigger 150106207 is not a GRB DATE: 15/01/06 09:40:34 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 442213126 / 150106207 at 04:58:43.25 UT on the 6th of January 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17287 SUBJECT: Fermi GBM trigger 150108121 is not a GRB DATE: 15/01/08 04:29:17 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 442378493 / 150108121 at 02:54:50.07 UT on 8 January 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17303 SUBJECT: Swift detection of the variable star SZ Psc DATE: 15/01/15 09:36:31 GMT FROM: Kim Page at U.of Leicester V. D'Elia (ASDC), M. De Pasquale (INAF-IASFPA), P. A. Evans (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), T. Sakamoto (AGU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 09:08:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source (trigger=625898). Swift slewed immediately to this location. The BAT on-board calculated location is RA, Dec 348.364, +2.679 which is RA(J2000) = 23h 13m 27s Dec(J2000) = +02d 40' 45" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is a 320-s image trigger. As is usual with an image trigger, the rapidly available BAT light curve shows no significant features. The XRT began observing the field at 09:15:03.4 UT, 380.5 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 348.3493, 2.6753 which is equivalent to: RA(J2000) = +23h 13m 23.83s Dec(J2000) = +02d 40' 31.1" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 54 arcseconds from the BAT onboard position, within the BAT error circle. This position is 4.1 arcseconds from that of a known X-ray source: XMMSL1 J231323.5+024033 in the XMM-NEWTON XMMSLEWCLN catalogue, also known as SZ Psc, a RS CVn variable type. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 3.72e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 389 seconds after the BAT trigger. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The source appears saturated. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17304 SUBJECT: The Swift Detection of a Large Flare from the RS CVn Binary SZ Psc DATE: 15/01/17 02:49:07 GMT FROM: Hans Krimm at NASA-GSFC S.A. Drake (CRESST/USRA/GSFC), R.A. Osten (STScI), H. A. Krimm (CRESST/USRA/GSFC), M. De Pasquale (IASF/INAF Palermo), N. Gehrels (NASA/GSFC), S. Barthelmy (NASA/GSFC) The Swift team reports the detection and preliminary analysis of a large flare from the 3.966-day period RS CVn binary star system SZ Psc (first reported in D'Elia et al. 2015, GCN Circ. 17303) which triggered the Swift Burst Alert Telescope (BAT) hard X-ray detector at T0 = 09:08:42 on 15 January 2015. Using the data set from T0-239 to T0+963 sec (where T0 is the BAT trigger time) from the recent telemetry downlink, we report further analysis of this BAT trigger. The mask-weighted light curve shows that the source entered the BAT field of view about 100 seconds before the start of the trigger interval and that the count rate appeared to be falling from an earlier peak during this time. During and after the 320-sec trigger interval, the rate was variable, with multiple peaks and an average rate of around 0.02 ct/s/cm2 (15-50 keV) or ~100 mCrab. The partial coding was 100%. Based on results from the BAT transient monitor, the source remained significantly above background until at least 14:25 UT on 15 January 2015. The time-averaged BAT spectrum from T0+0.0 to T0+320.0s is well fitted by either a simple power-law model or a thermal bremmstrahlung model. The power law index of the best fit to the time-averaged spectrum for this model is 3.16 +/- 0.50, while the temperature of the best-fit bremmstrahlung model is 16.2 (+8.0, -5.3) keV. The fluence in the 15-150 keV band is 4.3 +/- 1.1 x 10^-7 erg/cm^2. All the quoted errors are at the 90% confidence level. Searches of archival data from the BAT monitor shows that the source has not previously been detected in the monitor. The Swift X-Ray Telescope (XRT) started observing SZ Psc at T0(BAT)+380.5s. The soft X-ray (0.3-10 keV) rate was then ~90 ct/s, corresponding to 3.7 X 10^-9 erg/cm^2/s. The initial and all subsequent XRT observations during the first day were made in Windowed Timing mode, and thus, despite the fairly bright V magnitude of 7.44 should not be affected by optical loading. The XRT count rate increased to ~100 ct/s by the end of the initial observation at T0(BAT)+2200s, and then over the next 8 hours declined rapidly, dropping to ~30 ct/s at T0+30000s. After a a gap of ~16000s, further XRT observations from the period from T0+58000s to T0+92000s decayed much more slowly from a count rate of ~7 to 3 ct/s. At the end of these observations the soft X-ray flux of SZ Psc of 6.1 X 10^-11 erg/cm^2/s was within a factor of 2 of the flux observed in previous observations of this source, e.g., the ROSAT All-Sky Survey Bright Source Catalog quotes a count rate equivalent to a flux of 4.3 X 10^-11 erg/cm^/s (0.1 - 2.4 keV), and the XMM-Newton Slew Survey detection of 23.7 ct/s implies a flux of 3.2 X 10^-11 erg/cm^2/s (0.2-12 keV). Preliminary spectral analysis of the XRT data in the 0.5-10 keV band for the first XRT observation (the soft X-ray rise phase) using a 1T APEC fit yields a temperatures of 21.2 (+0.9,-0.8) keV in agreement with the initial BAT measurement. The inferred metallicity is somewhat subsolar (Z = 0.7). The Swift Ultraviolet/Optical Telescope (UVOT) observations of the flare peak and early decay phases of this optically bright source were saturated as noted in the GCN referred to above. The peak XRT flux of 4.1 X 10^-09 corresponds to an X-ray luminosity of 4.6 X 10^33 erg/s at the 97 pc distance of this system (van Leeuwen 2007, A&A, 474, 653) which is ~10% the combined systemic bolometric luminosity of 4.3 X 10^34 erg/s. Flares with X-ray luminosities > 1.0 X 10^33 erg/s have been detected from only a few active binaries previously, e.g., the flare of UX Ari on 2014-07-15 reported by Krimm et al, ATel #6319. The flare of SZ Psc is the most luminous flare in X-rays ever seen from any active late-type star to our knowledge. It is the third such large flare seen from this binary system, with 2 somewhat weaker ones previously detected by the MAXI/GSC (see Negoro et al., ATel #3737). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17306 SUBJECT: Trigger 626581: Swift detection of GRO J1008-57 DATE: 15/01/18 01:11:05 GMT FROM: David Palmer at LANL D. N. Burrows (PSU), V. D'Elia (ASDC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 00:34:50 UT, the Swift Burst Alert Telescope (BAT) triggered and located the source GRO J1008-57 (trigger=626581). Swift did not slew to this source due to an Earth limb constraint. The BAT on-board calculated location is RA, Dec 152.370, -58.275 which is RA(J2000) = 10h 09m 29s Dec(J2000) = -58d 16' 30" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT lightcurve is not yet available for time interval covering this 10-minute image trigger. A few kiloseconds of XRT/UVOT observation is planned. This source has been rising steadily for the past 10 days in a bright apastron outburst (see Kreschmar et al. ATEL 6917). The BAT lightcurve can be seen at http://swift.gsfc.nasa.gov/results/transients/GROJ1008-57/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17354 SUBJECT: Swift Trigger 628458 likely not astrophysical DATE: 15/01/27 11:52:19 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT P. D'Avanzo (INAF-OAB), P. A. Evans (U Leicester), J. A. Kennea (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift Team: At 11:25:54 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=628458). Swift slewed immediately to the burst. This was a sub-threshold image trigger spatially coincident with the galaxy NGC 4570. The BAT on-board calculated location is RA, Dec 189.211, +7.330 which is RA(J2000) = 12h 36m 51s Dec(J2000) = +07d 19' 47" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 11:37:57.7 UT, 722.9 seconds after the BAT trigger. No source was detected in 606 s of promptly downlinked data, which covered 90% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 726 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17367 SUBJECT: Swift Trigger 629206 is likely 1RXS J180408.9-342058 DATE: 15/01/31 21:53:21 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), K. L. Page (U Leicester) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 21:14:18 UT, the Swift Burst Alert Telescope (BAT) triggered on likely 1RXS J180408.9-342058 (trigger=629206). Swift did not slew because of Sun observing constraint. The BAT on-board calculated location is RA, Dec 271.033, -34.312 which is RA(J2000) = 18h 04m 08s Dec(J2000) = -34d 18' 42" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (20 mins), the BAT light curve shows nothing in the TDRSS real-time light curve. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 00:23 UT on 2015 February 06. There will thus be no XRT or UVOT data for this trigger before this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17393 SUBJECT: Fermi GBM trigger 150202624 is not a GRB DATE: 15/02/04 00:19:25 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 444581874 / 150202624 at 14:57:51.77 UT on 02 Feb 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17394 SUBJECT: Swift Trigger 629693: probably not real DATE: 15/02/04 00:34:54 GMT FROM: David Burrows at PSU/Swift M. H. Siegel (PSU), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), C. Gronwall (PSU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 00:12:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150204A (trigger=629693). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 207.806, -8.686 which is RA(J2000) = 13h 51m 13s Dec(J2000) = -08d 41' 08" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This was an image trigger and, as usual for such events, does not show any noticeable structure. The XRT began observing the field at 00:15:04.5 UT, 141.7 seconds after the BAT trigger. No source was detected in 468 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 58 seconds with the White filter starting 858 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. Given the lack of a bright XRT source, it is likely that this is a noise event and not an astrophysical source. The full ground-linked data set will be necessary to verify. Burst Advocate for this burst is M. H. Siegel (siegel AT swift.psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17403 SUBJECT: Swift Trigger 629693 was a noise event DATE: 15/02/04 16:00:42 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/PSU), H. A. Krimm (GSFC/USRA), M. H. Siegel (PSU) report on behalf of the Swift team: Examination of the full BAT data set for Swift trigger 629693 (Siegel et al., GCN 17394) shows no evidence for detection of a source and only apparently random fluctuations in the light curve. XRT observed the field for 1.5 ks. No source is detected in the instrument field of view. The 3-sigma upper limit at the BAT position reported in GCN 17394 is 3.15 x 10^-2 c/s (~ 1.6 x 10^-12 erg cm^-2 s^-1). We conclude that this trigger was not caused by an astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17416 SUBJECT: Trigger 630047: Swift detection of 1RXS J180408.9-342058 DATE: 15/02/06 21:26:24 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), D. N. Burrows (PSU), C. Gronwall (PSU), M.E. Gropp (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 20:45:14 UT, the Swift Burst Alert Telescope (BAT) triggered and located 1RXS J180408.9-342058 (trigger=630047). Swift slewed to the source. The BAT on-board calculated location is RA, Dec 271.019, -34.318, which is RA(J2000) = 18h 04m 05s Dec(J2000) = -34d 19' 03" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (15 min integration), there is nothing discernible from the real-time data. The XRT began observing the field at 21:04:28.5 UT, 1153.7 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 271.0338, -34.3481 which is equivalent to: RA(J2000) = +18h 04m 8.11s Dec(J2000) = -34d 20' 53.2" with an uncertainty of 5.3 arcseconds (radius, 90% containment). This location is 116 arcseconds from the BAT onboard position, within the BAT error circle. This position is 4.8 arcseconds from a known X-ray source: 1SXPS J180408.1-342048. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.0256 +/- 0.0020 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ180408.1-342048 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.37e-09 erg cm^-2 s^-1 (0.2-10 keV), corresponding to ~30 counts per second. UVOT took a finding chart exposure of 150 seconds with the White filter starting 1163 seconds after the BAT trigger. There is an optical counterpart in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 18:04:08.40 = 271.03499 DEC(J2000) = -34:20:51.2 = -34.34755 with a 90%-confidence error radius of about 0.62 arc sec. This position is 4.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.29 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.48. This is the second BAT trigger on 1RXS J180408.9-342058. The first was on January 31st, 2015 at 21:14UT (GCN #17367). The recent rise in brightness of this object has been reported by the BAT Transient Monitor (ATEL #6997) and MAXI (ATEL #7008). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17479 SUBJECT: Trigger 631747: Swift detection of 4U 0614+09 DATE: 15/02/19 17:02:25 GMT FROM: David Palmer at LANL A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 16:42:23 UT, the Swift Burst Alert Telescope (BAT) triggered on a burst from the source 4U 0614+09 (trigger=631747). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 94.300, +9.116 which is RA(J2000) = 06h 17m 12s Dec(J2000) = +09d 06' 57" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak burst with a duration of about 2 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 16:44:26.2 UT, 122.6 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 94.2808, 9.1369 which is equivalent to: RA(J2000) = +06h 17m 7.39s Dec(J2000) = +09d 08' 12.8" with an uncertainty of 5.1 arcseconds (radius, 90% containment). This location is 101 arcseconds from the BAT onboard position, within the BAT error circle. This position is 1.4 arcseconds from a known X-ray source: 4U 0614+09. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 30.40 +/- 0.30 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ061707.4%2B090811 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 2.10e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 130 seconds after the BAT trigger. UVOT detects an 18th mag source whose position is consistent with a catalogued optical source. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This LMXRB has been seen many times by Swift. This is the brightest burst seen since September 2012. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17482 SUBJECT: Fermi GBM trigger 150220229 is not a GRB DATE: 15/02/20 10:12:43 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 446102993/150220229 at 05:29:50.59 UT on the 20th of February 2014, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17483 SUBJECT: Trigger 631946: Swift detection of H1745-203 DATE: 15/02/21 00:17:02 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), L. Izzo (URoma/ICRA) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 23:38:50 UT, the Swift Burst Alert Telescope (BAT) triggered and located H1745-203 (trigger=631946). Swift will slew to the source at ~00:30 UT. The BAT on-board calculated location is RA, Dec 267.227, -20.379, which is RA(J2000) = 17h 48m 54s Dec(J2000) = -20d 22' 42" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This was a 22-min image trigger, and as such there will be nothing visible in the real-time TDRSS light curve. This AT will be cancelled at about 02:30 UT. BAT has seen this source rising in flux since Feb 17. The BAT lightcurve can be seen at http://swift.gsfc.nasa.gov/results/transients/weak/H1745-203/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17485 SUBJECT: Swift detection of an outburst from SGR 1935+2154 DATE: 15/02/22 12:45:45 GMT FROM: David Burrows at PSU/Swift D. N. Burrows (PSU), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), T. Sakamoto (AGU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 12:16:26 UT and 12:31:11, the Swift Burst Alert Telescope (BAT) triggered twice on an outburst from SGR 1935+2154 (triggers=632158, 632159). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 293.724, +21.888 which is RA(J2000) = 19h 34m 54s Dec(J2000) = +21d 53' 16" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve for the first trigger shows a single-peaked structure with a duration of about 0.2 sec. The peak count rate was ~3200 counts/sec (15-350 keV), at ~0 sec after the trigger. The second light curve also shows a single-peaked structure with a duration of about 0.2 sec. The peak count rate was ~11,000 counts/sec (15350 keV), at ~0 sec after the second trigger. The XRT began observing the field at 12:17:48.1 UT, 82.0 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 293.7312, 21.8973 which is equivalent to: RA(J2000) = 19h 34m 55.50s Dec(J2000) = +21d 53' 50.3" with an uncertainty of 2.5 arcseconds (radius, 90% containment). This location is 41 arcseconds from the BAT onboard position, within the BAT error circle. This position is consistent with the XRT position reported for this source in Cummings et al. (ATel #6294). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.27 x 10^22 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 86 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This source was discovered by Swift in July 5, 2014 (Cummings et al, ATel #6294). This is the first activity since that time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17490 SUBJECT: SGR 1935+2154: Swift-BAT refined analysis DATE: 15/02/23 01:10:13 GMT FROM: Hans Krimm at NASA-GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Swift/BAT triggered twice within 15 minutes on successive outbursts from the soft gamma repeater SGR 1935+2154 (Burrows, et al., GCN Circ. 17485). These were triggers #632158 (trigger 1) and #632159 (trigger 2). Using the data set from T-61 to T+242 sec for trigger 1 and the data set from T-120 to T+183 set for trigger 2 from the recent telemetry downlinks, we report further analysis of the BAT detection of two outbursts from SGR 1935+2154. The BAT ground-calculated position from trigger 2 is RA, Dec = 293.722, 21.889 deg which is RA(J2000) = 19h 34m 53.2s Dec(J2000) = +21d 53' 19.1" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 15% for trigger 1 and 100% for trigger 2. For trigger 1, the mask-weighted light curve shows a single peak of total duration ~100 msec. T90 (15-350 keV) is 0.08 +- 0.02 sec (estimated error including systematics). For trigger 2, the mask-weighted light curve shows a single peak of total duration ~20 msec. T90 (15-350 keV) is 0.02 +- 0.008 sec (estimated error including systematics). For trigger 1, the time-averaged spectrum from T+0.00 to T+0.09 sec fit by a simple power-law model shows the power law index of 2.92 +- 0.44 (chi squared 48.50 for 57 d.o.f.). The fluence in the 15-150 keV band is 4.6 +- 1.1 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.45 sec in the 15-150 keV band is 1.3 +- 0.4 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 5.45 +- 1.30 keV (chi squared 50.26 for 57 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 22.17 +- 9.67 keV (chi squared 46.62 for 57 d.o.f.). A double blackbody fit shows the lower temperature of 4.13 +1.28 keV and the higher temperature of 12.69 (error not unconstrained) keV (chi squared 44.57 for 55 d.o.f.). All the quoted errors are at the 90% confidence level. For trigger 2, the time-averaged spectrum from T-0.00 to T+0.02 sec fit by a simple power-law model shows the power law index of 2.83 +- 0.13 (chi squared 74.87 for 57 d.o.f.). The fluence in the 15-150 keV band is 4.4 +- 0.4 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.49 sec in the 15-150 keV band is 0.9 +- 0.1 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 7.92 +- 0.62 keV (chi squared 63.19 for 57 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 28.34 +- 3.59 keV (chi squared 45.19 for 57 d.o.f.). A double blackbody fit shows the lower temperature of 4.13 +1.22 keV and the higher temperature of 10.46 (error not unconstrained) keV (chi squared 42.09 for 55 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/632158/BA/ http://gcn.gsfc.nasa.gov/notices_s/632159/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17492 SUBJECT: Fermi GBM trigger 150223068 is not a GRB DATE: 15/02/23 02:29:57 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 446348290/150223068 at 01:38:07.99 UT on the 23rd of February 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to the outburst from SGR 1935+2154. This is the third such burst that triggered GBM since the outburst was detected by Swift BAT and reported in Burrows et al. (GCN #17485). GBM observations will be reported in more detail in an upcoming circular." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17496 SUBJECT: Fermi GBM Observations of SGR 1935+2154 DATE: 15/02/23 08:28:08 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) and G. Younes (GWU) report on behalf of the Fermi GBM Team: "At 17:57:05.99 UT on 23 February 2015, the Fermi Gamma-Ray Burst Monitor triggered (446320628/150222748) on a burst from SGR 1935+2154, which was reported to be in outburst by Burrows et al. (GCN 17485). The GBM burst occurred over 5 hours after the bursts detected by the Swift BAT. The GBM on-ground location is consistent with the known source position. The burst consists of a single pulse, with a duration of about 0.05 s. The burst is well-fit with a power law function with an exponential high-energy cutoff parameterized as Epeak = 29 +/- 1 keV and an Index -0.25 +/- 0.31. The corresponding peak flux integrated over 16ms (10-1000 keV) is (146 +/- 8)E-06 erg/s/cm^2. The fluence during T0-0.048s to T0+0.000s is (1.6 +/- 0.1)E-07 erg/cm^2. A fit to a double black-body spectrum is a statistical tie with the exponential power-law fit, with one extra parameter and blackbody temperatures of 4.3 +/- 0.7 keV and 10.4 +/- 1.0 keV. The other models reported in Krimm et al. (GCN 17490) are not statistically favored. This burst was followed by four further triggers at 19:44:16.94 UT (trigger 446327059/150222822) on 22 February 2015, 01:38:07.99 UT (446348290/150223068), 05:24:54.16 UT (446361897/150223226), and 06:45:40.13 UT (446366743/150223282) on 23 February 2015, all consistent with being from SGR 1935+2154. All of these triggers consist of a single peak. The third trigger, 150223068, is several times more intense than the others, which are of about equal intensity. The analysis results presented above are preliminary. These bursts are bright enough that some are being classified by the flight software as GRBs. We will correct this classification in the online catalog at the Fermi Science Support Center: http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigtrig.html but will not issue further circulars to correct the classification." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17507 SUBJECT: Trigger 632888: Swift detection of the magnetar 4U 0142+61 DATE: 15/02/28 05:11:06 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 04:53:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located 4U 0142+61 (trigger=632888). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 26.571, +61.768, which is RA(J2000) = 01h 46m 17s Dec(J2000) = +61d 46' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows 4 short spikes (<~0.1 s) over a total duration of about 20 sec. The peak count rate was ~8000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 04:54:43.2 UT, 78.3 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 26.5966, 61.7519 which is equivalent to: RA(J2000) = +01h 46m 23.18s Dec(J2000) = +61d 45' 06.8" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 72 arcseconds from the BAT onboard position, within the BAT error circle. This position is 7.3 arcseconds from a known X-ray source: 1SXPS J014622.3+614502. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 4.610 +/- 0.021 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ014622.3%2B614502 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 150 seconds with the White filter starting 90 seconds after the BAT trigger. No credible counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. This source has been previously detected by BAT on timescales of both minutes and milliseconds, most recently on February 19 of this year. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17508 SUBJECT: Fermi GBM Observations of Magnetar 4U 0142+61 DATE: 15/02/28 16:57:32 GMT FROM: Oliver Roberts at UCD/Fermi O.J Roberts (UCD) reports on behalf of the Fermi GBM Team: "At 04:53:25.04 UT on the 28th of February 2015, the Fermi Gamma-Ray Burst Monitor triggered (446792008/150228204) on a burst from magnetar 4U 0142+61, which was also reported by Barthelmy et al. (GCN 17507). The GBM on-ground location is consistent with the known source position. The triggered event consists of 4-5 bursts, each with a duration of about 0.1s, that occur over a duration of about 20s. The two brightest bursts occur at T0-0.06s and T0+10.0s. The burst at T0+10s is well-fit with a power law function with an exponential high-energy cutoff. The power law index is -0.38 +/- 0.33 and the cutoff energy, parameterised as Epeak, is 74 +/- 8 keV. The fluence during T0+10.048s to T0+10.304s is (2.703 +/- 0.384)E-07 erg/cm^2. The corresponding peak flux integrated over 16ms (10-1000 keV) is (11 +/- 1)E-06 ph/s/cm^2. The second burst at T0-0.064s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.31 +/- 0.39 and the cutoff energy, parameterised as Epeak, is 55 +/- 5 keV. The fluence during T0-0.064s to T0+0.064s is (2.716 +/- 0.241)E-07 erg/cm^2. The corresponding peak flux integrated over 16ms (10-1000 keV) is (18 +/- 1)E-06 ph/s/cm^2. This burst was followed by another trigger at 05:06:55.63 UT (trigger 446792818/150228213) on the 28th of February 2015, and is also consistent with being from magnetar 4U 0142+61. This trigger consists of a bright, short (t<~0.3s) single peak. The analysis results presented above are preliminary. These bursts are bright enough that some are being classified by the flight software as GRBs. We will correct this classification in the online catalogue at the Fermi Science Support Center: http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigtrig.html but will not issue individual circulars to correct the classification for triggers from this source." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17509 SUBJECT: Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888) DATE: 15/02/28 18:00:56 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT trigger #632888 on 4U 0142+61 (Barthelmy, et al., GCN Circ. 17507). The BAT ground-calculated position is RA, Dec = 26.603, 61.746 deg, which is RA(J2000) = 01h 46m 24.8s Dec(J2000) = +61d 44' 47.4" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows multiple spikes from the source. The event-by-event data starts at T-240 sec. The first emission is at ~T-9 sec and may be several unresolved spikes or a single outburst with a duration of ~1 sec. Then come 4 splikes (durations less than ~50 msec), then a bright spike at ~T+0 sec, then spikes at T+{10, 15, 65, 72, and 247} sec, all with durations < 75 msec. Then the source goes out of the BAT FOV at ~T+430 sec. T90 (15-350 keV) is 187 +- 114 sec (estimated error including systematics). The time-averaged spectrum from T-9.08 to T+273.78 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.01 +- 0.29. The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+9.24 sec in the 15-150 keV band is 2.1 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/632888/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17512 SUBJECT: Trigger 633105 is likely not a GRB DATE: 15/03/01 07:00:38 GMT FROM: Amy Lien at GSFC A. Y. Lien (GSFC/UMBC), A. Maselli (INAF-IASFPA) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 06:20:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source close to M31 (NGC224) (trigger=633105). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 11.332, +41.857 which is RA(J2000) = 00h 45m 20s Dec(J2000) = +41d 51' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 20 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 06:22:32.4 UT, 98.3 seconds after the BAT trigger. No source was detected in 604 s of promptly downlinked data, which covered 91% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 102 seconds after the BAT trigger. No new source has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. Given the lack of a bright XRT source and the proximity of the BAT trigger to M31, it is possible that this is a noise event and not an astrophysical source. However, we note that the BAT image significance is 8.75. The full ground-linked data set will be necessary to verify. Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17514 SUBJECT: Swift Trigger 633173 is probably not an astrophysical source DATE: 15/03/01 18:25:04 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. M. Chester (PSU), M. De Pasquale (INAF-IASFPA), N. Gehrels (NASA/GSFC), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 17:58:50 UT, the Swift Burst Alert Telescope (BAT) triggered and located a likely noise event (trigger=633173). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 139.480, -22.437, which is RA(J2000) = 09h 17m 55s Dec(J2000) = -22d 26' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, nothing shows up in the real-time TDRSS light curve. No XRT counterpart was detected in 980 s of promptly downlinked data. UVOT took a finding chart exposure of 250 seconds with the U filter starting 341 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 21% of the BAT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.10. This event alerted as part of a program to follow up low-significance possible detections in the direction of nearby galaxies. Due to the marginal significance of the detection (6.16 sigma) the distance of the event from the putative host galaxy (5 arcminutes, about twice the galaxy's nominal radius) and the lack of a detection by the XRT and UVOT, we believe that this is not an astrophysical detection. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17546 SUBJECT: Fermi GBM trigger 150305751 is not a GRB DATE: 15/03/05 19:35:54 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 447271330/150305751 at 18:02:07.48 UT on the 5th of March 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17547 SUBJECT: Further UVOT Observations of Swift J0045.2+4151 DATE: 15/03/06 00:54:19 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel, L.M.Z. Hagen (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift UVOT team: Swift continues to observe the field of BAT trigger 633105 (formerly GRB 150301C, now Swift J0045.2+4151) with a sky location in M31. The UVOT data show no change in brightness in the optical source reported in Hagen & Lien (GCN Circ 17541). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the most recent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag v 338602 338728 124 >18.25 b 337955 338082 124 >19.12 u 337824 337951 124 18.45+-0.27 uvw1 337564 337819 250 18.82+-0.26 uvm2 326044 343973 4048 18.64+-0.06 uvw2 338088 338597 500 18.72+-0.14 All of these magnitudes are consistent, within uncertainties, of our initial and archival measures. We further report an analysis of 207 ks of archival UVOT data for the source. Our analysis shows no previous variability in the source in the UVOT photometry, which has a typical uncertainty of 0.2 mag in the three UV filters. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17548 SUBJECT: Swift J0045.2+4151: analysis of XMM-Newton archival data DATE: 15/03/06 15:28:51 GMT FROM: Sandro Mereghetti at IASF/CNR A. Belfiore (INAF/IASF Milano), A. Tiengo (IUSS Pavia), G. L. Israel (INAF/OA Roma), A. M. Read (U. Leicester), R. Salvaterra, D. Salvetti (INAF/IASF Milano), G. Novara (IUSS Pavia), S. Mereghetti, M. Marelli (INAF/IASF Milano), G. Rodriguez (INAF/OA Roma), G. Lisini (IUSS Pavia), S. R. Rosen (U. Leicester), A. De Luca  (INAF/IASF Milano), report on behalf of the EXTraS collaboration: Based on the preliminary results of the EXTraS project (DeLuca et al. 2015, arXiv:1503.01497), we report on the analysis of XMM-Newton archival data of 3XMM J004514.7+415035 (aka [PFH2005] 622, Pietsch et al. 2005, ApJ 434, 483), the candidate X-ray counterpart of GRB 150301C  (aka Swift J0045.2+4151, GCN Circ 17512, 17516, 17536, 17544). The source is detected by the EPIC instrument at a 0.2-12 keV flux level of ~10^-14 erg/cm^2/s in two observations (2002-01-26 and 2007-01-05), while only upper limits of ~5x10^-14 erg/cm^2/s can be set from 5 shorter observations performed in July 2006. Shallow upper limits of ~10^-12 erg/cm^2/s can be derived from three non-detections during slew observations on 2005-07-03, 2007-01-06, and 2010-01-31. The EPIC light curves of the two observations show no evidence for variability. The search for coherent pulsations in the PN data, between 0.15 and 10^4 s, gives negative results. The blind search for transients does not report any significant candidates within the BAT error circle of GRB 150301C in any of the seven XMM-Newton observations. We extracted the EPIC spectra of 3XMM J004514.7+415035 and, after verifying that there are no significant spectral differences between the two observations, we fit them simultaneously with an absorbed power-law model. The best-fit parameters (errors at the 90% confidence level) are N_H<3x10^21 cm^-2 and photon index 1. 9 (-0.6, +0.8). Fixing the N_H to the Galactic value of 10^21 cm^-2, as appropriate for sources in the M31 disk, the photon index can be constrained in the 1.6-2.2 range (C-stat=142 for 143 degrees of freedom) and the unabsorbed flux in the 0.1-10 keV range is (1.3 +/- 0.3) x10^-14 erg/cm^2/s, corresponding to ~6x10^35 erg/s at the M31 distance. We note that the properties of 3XMM J004514.7+41503 are consistent with those of an active magnetar, like, e.g., SGR1806-20, at the distance of M31. Considering that the duration, fluence and spectrum of the burst detected by BAT are compatible with an intermediate flare from a magnetar in M31, 3XMM J004514.7+41503 might be considered as a magnetar candidate in the Andromeda galaxy. Plots of the long term flux evolution, the background-subtracted and exposure-corrected light curves, and the power density spectra with pulsed fraction upper limits can be found on the EXTraS website: http://www.extras-fp7.eu/index.php/home/90-extras/news/158-gcn-atel-1 EXTraS ("Exploring the X-ray Transient and variable Sky") is a project aimed at the systematic exploitation of the XMM/EPIC database, to search for, and characterize variability (both periodic and aperiodic), to search for new transients and to provide a phenomenological classification of variable sources. All EXTraS results, products and tools will be released to the community at the end of the project. EXTraS is carried out by a collaboration including INAF (Italy), IUSS (Italy), CNR/IMATI (Italy), University of Leicester (UK), MPE (Germany) and ECAP (Germany) and has been funded within the EU-FP7 framework (grant agreement n. 607452). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17550 SUBJECT: Fermi GBM trigger 150307942 is not a GRB DATE: 15/03/07 23:43:33 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 447460597/150307942 22:36:34.87 UT on the 7th of March 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17563 SUBJECT: Fermi GBM trigger 150311331 is not a GRB DATE: 15/03/11 10:49:26 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 447753382/150311331 at 07:56:19.87 UT on the 11th of March 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17571 SUBJECT: Fermi GBM trigger 150312827 is not a GRB DATE: 15/03/12 20:28:00 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 447882634/150312827 at 19:50:31.31 UT on the 12th of March 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17601 SUBJECT: Swift Trigger 635306 is probably not an astrophysical source DATE: 15/03/18 11:22:08 GMT FROM: David Palmer at LANL A. A. Breeveld (UCL-MSSL), P. A. Evans (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), C. J. Mountford (U Leicester), C. Pagani (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 10:54:26 UT, the Swift Burst Alert Telescope (BAT) imaged a peak with a projected location near IC 749 (trigger=635306). Swift slewed immediately to the location to confirm or refute the presence of a source. The BAT on-board calculated location is RA, Dec 183.006, +12.037, which is RA(J2000) = 12h 12m 02s Dec(J2000) = +12d 02' 11" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers, there is no significant variation in the immediately available BAT lightcurve. The XRT began observing the field at 10:56:52.9 UT, 146.3 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. No source is detected in the UVOT in the initial images. Because this is a low significance peak (5.48 sigma) in a 64s image made without a rate trigger, it was only considered to be of possible note because it was in the proximity of the nearby galaxy IC 749. It had an offset of 9 arcminutes for this galaxy, which is well outside of its luminous region. In such cases, Swift triggers a follow-up observation to test whether the source is real. In the absence of an XRT or UVOT confirmation, it is unlikely that this event is anything more than a noise fluctuation. Full determination of the reality of this event will require the full downlinked dataset. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17607 SUBJECT: Confirmation that Swift trigger 635306 is not an astrophysical source DATE: 15/03/18 21:50:04 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA) and C. Pagani (U Leicester) report on behalf of the Swift Team: We conclude that Swift trigger #635306 (Breeveld, et al., GCN Circ. 17601) was the result of noise fluctuations and is not due to a GRB or other astrophysical event. We have analyzed the BAT data set from T-239 to T+963 sec from the recent telemetry downlink. We find that there is no sign of significant emission from the trigger location at any point in this interval. XRT observations in Photon Counting mode data started 164 s after the BAT trigger. In 1ks of PC data no source is detected inside the BAT error circle. The three sigma upper limit is 6e-3 counts/second. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17609 SUBJECT: Fermi GBM trigger 150319666 is not a GRB DATE: 15/03/19 16:44:54 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 448473511/150319666 at 15:58:28.41 UT on the 19th of March 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17610 SUBJECT: Swift Triggers 635788-635794 are probably not real. DATE: 15/03/22 09:12:12 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U Leicester), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), C. J. Mountford (U Leicester) and P. Romano (INAF-IASFPA) report on behalf of the Swift Team: Between 08:10:02 UT and 09:03:38 UT Swift reported 5 triggers, all of which were 64-s image triggers. Trigger 635788 which was identified as possibly being on the known source GRS 1915+105 and the rest (635789, 635790, 635792, 635794) on unknown sources. All of these triggers occurred while the star trackers had lost lock. Prompt images show that Swift was not stationary while taking these observations. We believe therefore that these are spurious triggers and are not astrophysical, however until we get the full ground dataset we are unable to say this for certain. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17676 SUBJECT: Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB DATE: 15/04/04 22:24:45 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, D.Denisenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB150404.73 (Fermi trigger 449861706) 8 sec after notice time and 41 sec after trigger time at 2015-04-04 17:35:45 UT. On our first (10s exposure) set we found 1 optical transient within FERMI error-box (ra=11 05 45 dec=-69 34 46 r=9.720000) in one polarization: MASTER OT J110859.75-693818.9 RA = 11h 08m 59.75s Dec = -69d 38m 18s.9 m_OT=14.8. We have 2 pair images in 2 different polarization. The first pair started 2015-04-04 17:35:45 , 10s exposition. The second pair (20-s exposition) started on 2015-04-04 17:36:25, and there is no optical candidate on it. The 5-sigma upper limit has been about 15.8 mag. The possible OT image is available at http://observ.pereplet.ru/GRB150404.73.jpg The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17679 SUBJECT: Swift triggered on a source in Terzan 5 (trigger=637212) DATE: 15/04/05 18:45:15 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 18:15:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source within Terzan 5 (trigger=637212). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 267.000, -24.772 which is RA(J2000) = 17h 48m 00s Dec(J2000) = -24d 46' 18" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image trigger, there is nothing in the real-time TDRSS BAT light curve. The XRT began observing the field at 18:24:47.4 UT, 580.8 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 267.0200, -24.7801 which is equivalent to: RA(J2000) = +17h 48m 4.80s Dec(J2000) = -24d 46' 48.4" with an uncertainty of 5.4 arcseconds (radius, 90% containment). This location is 71 arcseconds from the BAT onboard position, within the BAT error circle. This position is 1.44 arcseconds from a known X-ray source EXO 1745-248. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.34e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 589 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain extinction expected. We note that the source EXO 1745-248 within Terzan 5 is currently in outburst, so we suggest this may be the cause of the trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17686 SUBJECT: Swift detection of SAX J1808.4-3658 DATE: 15/04/11 19:57:28 GMT FROM: David Palmer at LANL D. Malesani (DARK/NBI), D. M. Palmer (LANL) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 19:36:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from SAX J1808.4-3658 (trigger=637765). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 272.073, -36.974 which is RA(J2000) = 18h 08m 18s Dec(J2000) = -36d 58' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 20 sec. The peak count rate was ~2400 counts/sec (15-350 keV), at ~6 sec after the trigger. The XRT began observing the field at 19:37:11.2 UT, 46.1 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 272.1135, -36.9774 which is equivalent to: RA(J2000) = +18h 08m 27.24s Dec(J2000) = -36d 58' 38.6" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 117 arcseconds from the BAT onboard position, within the BAT error circle. This position is 6.7 arcseconds from a known X-ray source: SAX J1808.4-3658. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.3550 +/- 0.0038 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ180827.6-365843 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 6.62e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 54 seconds after the BAT trigger. The source is clearly visible in the UVOT image, but the crowded field prevents automatic estimation of its brightness at this time. This source is currently in outburst (Sanna et al., ATel 7364). Its BAT lightcurve is given at http://swift.gsfc.nasa.gov/results/transients/weak/SAXJ1808.4-3658/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17687 SUBJECT: Swift trigger 637807 is probably not an astrophysical source DATE: 15/04/12 08:57:02 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 08:32:10 UT, the Swift Burst Alert Telescope (BAT) imaged a peak with a projected location near XTE J1814-338 (trigger=637807). Due to a visibility constraint, Swift did not slew immediately to the location. The BAT on-board calculated location is RA, Dec = 273.356, -33.940, which is RA(J2000) = 18h 13m 25s Dec(J2000) = -33d 56' 124" with an uncertainty of 4 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers, there is no significant variation in the immediately available BAT lightcurve. Given the very low significance of the trigger (5.87 sigma), and that the BAT position is more than 10 arcmin away from the known position of XTE J1814-338, we do not believe that the trigger is associated with XTE J1814-338 and it is unlikely to have been caused by a real astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17699 SUBJECT: IPN Triangulation of a bright burst from SGR 1935+2154 DATE: 15/04/14 13:03:18 GMT FROM: Dmitry Svinkin at Ioffe Institute S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: A bright, short-duration, soft burst has been observed by Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND), so far, at about 41064 s UT (11:24:24) on April 12. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 293.489 (19h 33m 57s) +22.543 (+22d 32' 35") Corners: 293.060 (19h 32m 14s) +23.547 (+23d 32' 50") 293.029 (19h 32m 07s) +24.004 (+24d 00' 14") 293.918 (19h 35m 40s) +21.515 (+21d 30' 54") 293.951 (19h 35m 48s) +21.033 (+21d 02' 00") --------------------------------------------- The error box area is 1118 sq. arcmin, and its maximum dimension is 3 deg (the minimum one is 7 arcmin). The Sun distance was 84 deg. This box may be improved. The position of SGR 1935+2154 (Stamatikos et., al. GCN Circ. 16520; Lien et al., GCN Circ. 16522; Cummmings et al., ATel #6294) is inside the box at 41 arcmin from its center (at 0.8 arcmin from the center line of the 7 arcmin wide Konus-HEND annulus). Given the positional coincidence of this burst with SGR 1935+2154 and softness of its spectrum (as observed by Konus-Wind), we conclude this burst is likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/150412_T41064/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17703 SUBJECT: Konus-Wind observation of a bright burst from SGR 1935+2154 DATE: 15/04/14 15:02:18 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, report: A bright, short-duration, soft burst which is likely originated from SGR 1935+2154 (IPN triangulation: Golenetskii et al., GCN 17699) triggered Konus-Wind at T0=41064.683 s UT (11:24:24.683). The light curve shows a single pulse with a sharp(<10 ms) rise and a total duration of ~1.7 s. The emission is seen up to ~200 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/SGRs/150412_T41064/ As observed by Konus-Wind, the burst had a fluence of 2.60(-0.03,+0.03)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.800 s, of 2.3(-0.1,+0.1)x10^-5 erg/cm2/s (both in the 20 - 200 keV energy range). The time-averaged spectrum (measured from T0 to T0+9.472 s) is best fit in the 20 - 250 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = +0.21(-0.13,+0.13), and Ep = 36.5(-0.6,+0.6) keV (chi2 = 28.6/31 dof). A double blackbody fit to this spectrum yields the lower temperature kT1 = 6.4 (-0.7,+0.7) keV and the higher temperature kT2 = 12.3 (-0.6,+0.7) keV (chi2=36.3/30 dof). The rather long duration of the burst along with the large measured energy fluence put the burst in the class of "intermediate" SGR bursts. The measured spectral parameters are in typical range for bright short and intermediate SGR bursts; also, they resemble the fits reported by Swift/BAT and Fermi/GBM for much weaker and shorter bursts detected during the recent SGR 1935+2154 activity in February, 2015 (Lien et al., GCN 17490; Burns & Younes, GCN 17496). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17712 SUBJECT: Swift Trigger 638217 is probably not an astrophysical source DATE: 15/04/17 05:09:59 GMT FROM: David Palmer at LANL N. Gehrels (NASA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 04:52:50 UT, the Swift Burst Alert Telescope (BAT) detected a marginal significance peak in an non-rate-triggered image (trigger=638217). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 186.582, +15.433 which is RA(J2000) = 12h 26m 20s Dec(J2000) = +15d 25' 58" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 04:55:03.4 UT, 132.9 seconds after the BAT trigger. No source was detected in 147 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 135 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. This event triggered as part of program to follow-up marginal image triggers in proximity to nearby galaxies to confirm or refute weak events. In this case, the low significance (5.96 sigma), lack of a rate trigger, distance from the potential host galaxy (10 arcminutes from NGC 4421, which has a nominal diameter of 2.5 arcmin) and non-detection of any afterglow by XRT and UVOT implies that this is a noise fluctuation in the image, and not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17716 SUBJECT: Confirmation that Swift trigger 638217 is not an astrophysical source DATE: 15/04/17 14:49:12 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: We conclude that Swift trigger #638217 (Gehrels, et al., GCN Circ. 17712) was the result of noise fluctuations and is not due to a GRB or other astrophysical event. We have analyzed the BAT data set from T-239 to T+440 sec from the recent telemetry downlink. We find that there is no sign of significant emission from the trigger location at any point in this interval. XRT observations in Photon Counting mode data started 152 s after the BAT trigger. In 1.9 ks of PC data no source is detected inside the BAT error circle. The three sigma upper limit is 9.5e-3 counts/second. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17724 SUBJECT: Swift trigger 638589 is probably not an astrophysical source DATE: 15/04/20 17:30:30 GMT FROM: David Palmer at LANL W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (NASA/UMBC), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 17:00:10 UT, the Swift Burst Alert Telescope (BAT) detected a marginal significance peak in an non-rate-triggered image (trigger=638589). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 87.815, -10.422 which is RA(J2000) = 05h 51m 16s Dec(J2000) = -10d 25' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 17:09:20.0 UT, 549.5 seconds after the BAT trigger. No source was detected in 416 s of promptly downlinked data, which covered 85% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 1267 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.87. Because this is a marginal significance detection of a peak in a non-rate-triggered image, with no corresponding source in the XRT data, we believe that this is noise fluctuation and not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17764 SUBJECT: Trigger 639199: Swift detection of IGRJ16418-4532 DATE: 15/04/27 14:39:29 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 14:18:02 UT, the Swift Burst Alert Telescope (BAT) triggered and located IGRJ16418-4532 (trigger=639199). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 250.461, -45.533, which is RA(J2000) = 16h 41m 51s Dec(J2000) = -45d 31' 57" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers (duration 320 sec), the TDRSS real-time light curve does not show anything significant. The XRT began observing the field at 14:25:34.6 UT, 452.1 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 250.4627, -45.5410 which is equivalent to: RA(J2000) = 16h 41m 51.05s Dec(J2000) = -45d 32' 27.6" with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 29 arcseconds from the BAT onboard position, within the BAT error circle; and 7.7 arcseconds from the location of the known X-ray source IGRJ16418-4532 in the BAT catalogue. The XRT position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.6 arcseconds from that of a known X-ray source: 3XMM J164150.8-453225 in the XMM-NEWTON XMMSSC catalogue. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 149 seconds with the U filter starting 877 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17779 SUBJECT: Fermi GBM trigger 150424722 is not a GRB DATE: 15/04/28 15:23:15 GMT FROM: Binbin Zhang at UAH Bin-Bin Zhang (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 451588780/150424722 at 17:19:37.07 UT on the 24th of April 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles.†— Sent from Mailbox//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17799 SUBJECT: Swift Trigger 639636: a possible GRB DATE: 15/05/02 11:51:03 GMT FROM: Scott Barthelmy at NASA/GSFC A. Maselli (INAF-IASFPA), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 11:30:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB (trigger=639636). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 350.788, +7.897, which is RA(J2000) = 23h 23m 09s Dec(J2000) = +07d 53' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (7.4 sigma), there is nothing significant in the real-time light curve. The XRT began observing the field at 11:33:13.7 UT, 151.3 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 104 seconds with the White filter starting 502 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 16% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.11. Burst Advocate for this burst is A. Maselli (maselli AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17800 SUBJECT: Confirmation that Swift Trigger 639636 is not astrophysical DATE: 15/05/03 01:25:25 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), A. Maselli (INAF-IASFPA), M. Siegel (PSU), P. Kuin (MSSL) report: We conclude that Swift trigger #639636 (Maselli, et al., GCN Circ. 17799) was the result a noise fluctuation in BAT and is not due to a GRB or other astrophysical event. We have analyzed the BAT data set from T-239 to T+680 sec from recent telemetry downlinks. We find that ground analysis results in the significance dropping to 4.1 sigma from T+0 to T+60 s. Using 4.4 ks of XRT data, there is no significant counterpart detected within the BAT error circle at a three sigma upper limit of 2.84E-03 cts/s. The UVOT finding chart shows no new source to a limit of 19.6 mag in white. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17858 SUBJECT: Disreqard the recent cluster of Swift-related GCN Circulars DATE: 15/05/21 18:52:22 GMT FROM: Scott Barthelmy at NASA/GSFC A problem developed involving the automated processing scripts at the Swift MOC that generated a series of messages to be sent to the U. of Leicester automated processing which then produced the recent cluster of Circulars to be submitted to GCN and distributed. Please disregard Circulars 17842 through 17857; they are from old Swift TOO observations. The Swift Team apologies for the inconvenience. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17862 SUBJECT: Swift trigger 641332 is probably not an astrophysical source DATE: 15/05/23 09:10:08 GMT FROM: Caryl Gronwall at PSU/Swift-UVOT C. Gronwall (PSU), A. Y. Lien (GSFC/UMBC) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 08:49:06 UT, the Swift Burst Alert Telescope (BAT) detected a marginal significance peak in an non-rate-triggered image (trigger=641332). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 353.476, -35.987 which is RA(J2000) = 23h 33m 54s Dec(J2000) = -35d 59' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 08:51:27.7 UT, 141.3 seconds after the BAT trigger. No source was detected in 348 s of promptly downlinked data, which covered 98% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 145 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Because this is a marginal significance detection of a peak in a non-rate-triggered image, with no corresponding source in the XRT data, we believe that this is noise fluctuation and not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17867 SUBJECT: Confirmation that Swift Trigger 641332 is not astrophysical DATE: 15/05/24 02:31:20 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/USRA/GSFC) and C. Gronwall (PSU) report: We conclude that Swift trigger #641332 (Gronwall, et al., GCN Circ. 17862) was the result a noise fluctuation in BAT and is not due to a GRB or other astrophysical event. We have analyzed the BAT data set from T-239 to T+963 sec sec from recent telemetry downlinks. We find that ground analysis results in the significance dropping to 4.1 sigma from T+0 to T+40 s. There is also no significant source in the rapidly available UVOT data. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17887 SUBJECT: Fermi GBM trigger 150529948 is not a GRB DATE: 15/05/30 00:44:26 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 454632311/150529948 at 22:45:08.02 UT on the 24th of May 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17897 SUBJECT: Swift Triggers 642296 and 642297 are not GRBs DATE: 15/06/02 11:11:58 GMT FROM: David Palmer at LANL P. A. Evans (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 10:37:38 UT, the Swift Burst Alert Telescope (BAT) had lost star-tracker lock. As a result trigger 642296 and subsequent triggers are due to misidentifying known sources as new GRBs. The Flight Operations Team has been called in. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17901 SUBJECT: Swift Trigger 642453: a possible GRB DATE: 15/06/04 03:18:19 GMT FROM: David Palmer at LANL V. D'Elia (ASDC), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 03:00:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB (trigger=642453). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 238.343, -46.622 which is RA(J2000) = 15h 53m 22s Dec(J2000) = -46d 37' 19" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, there is no activity visible in the immediately-available lightcurve. The XRT began observing the field at 03:02:28.4 UT, 138.1 seconds after the BAT trigger. No source was detected in 35 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 96 seconds with the White filter starting 141 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.95. Due to the lack of a rate increase trigger, and the non-detection of a counterpart in the relatively short XRT observation, we cannot confirm that this is a real astrophysical source at this time. A determination of the reality of this event will require the full downlinked dataset and possibly further XRT observations. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17902 SUBJECT: Swift trigger 642453 is not an astrophysical source DATE: 15/06/04 14:58:01 GMT FROM: Valerio D'Elia at ASDC V. D'Elia (ASDC), S. D. Barthelmy (GSFC), P. A. Evans (U. Leicester), L. Izzo (URoma/ICRA) and M. H. Siegel (PSU) report on behalf of the Swift team: We have analysed 4.5 ks of Swift/XRT data for the Swift/BAT-detected possible burst GRB 150604A (D'Elia et al. GCN Circ. 17901), collected in Photon Counting mode, between 138 s and 21.6 ks after the BAT trigger. No X-ray sources have been detected inside or close to the Swift/BAT error region. The 3-sigma upper limit at the Swift/BAT position is ~0.002 ct s^-1, corresponding to a 0.3-10 keV observed flux of ~1e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). Ground analysis of the BAT data for this trigger shows that the significance of the initial detection has dropped below that considered to be a valid trigger. Swift/UVOT began settled observation of the field 142 s after the BAT trigger. No new source is detected in the initial 1.4 ks of observation down to a white magnitude limit of 20.9. Therefore, this trigger is likely due to noise, and not due to anything astrophysical. This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17916 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 455474712 / 150608698 is not a GRB DATE: 15/06/08 19:10:30 GMT FROM: George A. Younes at George Washington U Younes G. (GWU) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 455474712 / 150608698 at 16:45:09.95 UT on 08 June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to distant particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17919 SUBJECT: Trigger 643078: Swift detection of H1743-322 DATE: 15/06/10 12:21:12 GMT FROM: David Palmer at LANL N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 11:41:14 UT, the Swift Burst Alert Telescope (BAT) triggered and located a bright source, probably H1743-322, which is currently in outburst (Atel #7607; Zhang et al.). Due to a known race condition in the Swift BAT software, this was misidentified as a different location which corresponds to a different source. Since the misidentified source has a low catalog threshold, it was considered unusually bright, triggering a 'Transient Source' response. This included GCN Notices and a Swift follow-up repoint. The XRT began observing the field at 12:00:15.4 UT, 1141.1 seconds after the BAT trigger. No source was detected in 997 s of promptly downlinked data. UVOT took a finding chart exposure of 150 seconds with the White filter starting 1144 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. Because of the software race condition, H1743-322 was not in the XRT FOV after Swift slewed to the incorrect location. Preplanned observations of H1743-322 have already been made and more are scheduled. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17921 SUBJECT: Fermi GBM trigger 150612648 is not a GRB DATE: 15/06/12 16:09:40 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 455815977/150612648 at 15:32:54.55 UT on the 12th of June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a solar flare.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17922 SUBJECT: Fermi GBM trigger 150613619 is not a GRB DATE: 15/06/13 23:09:45 GMT FROM: Peter Jenke at MSFC "P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 455899872/150613619 at 14:51:09.66 UT on the 13th of June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17927 SUBJECT: Fermi GBM trigger 150615574 is not a GRB DATE: 15/06/15 14:59:34 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 456068761/150615574 at 13:45:58.47 UT on the 15th of June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to distant particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17929 SUBJECT: Swift trigger 643949 is V404 Cyg DATE: 15/06/15 18:55:32 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 18:31:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located V404 Cyg. Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 306.020, +33.850 which is RA(J2000) = 20h 24m 05s Dec(J2000) = +33d 50' 59" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 18:34:37.3 UT, 179.1 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 306.0162, 33.8673 which is equivalent to: RA(J2000) = 20h 24m 03.89s Dec(J2000) = +33d 52' 02.4" with an uncertainty of 2.4 arcseconds (radius, 90% containment). This location is 63 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 0.8 arcseconds from that of a known transient low-mass X-ray binary V* V404 Cyg. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 8.10 x 10^21 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 183 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17931 SUBJECT: Optical follow-up of Swift trigger on V404 Cyg DATE: 15/06/15 22:05:04 GMT FROM: Kosmas Gazeas at U of Athens Kosmas Gazeas and Konstantinos Sapountzis (National Univ. of Athens) report: Swift trigger 643949 occurred in June 15, 2015 and followed a few minutes afterwards with the 0.40 m f/8 robotic telescope at the University of Athens in R-band. Data collection has started on June 15 (UT) 18:58:37 and finishing on June 15 (UT) 20:28:09 (mid-exposure time). The bright GRB seems to be the X-ray binary V404 Cyg, consisting of a black hole and a late G-type companion. A sum of 30 exposures of 180 sec each was collected. Photometry with a 3 pixel (approximately 4 arcsec) radius aperture yields an R magnitude estimation of R = 12.65 +/- 0.01 mag in the beginning of data acquisition and R = 15.43 +/- 0.03 mag at the end. There is a luminosity fading trend of ~2.7 mag/hour as observed during the first hour of acquisition. Fading rate dramatically decreased afterwards, reaching the value of ~0.2 mag/hour. Differential photometry was performed utilizing the nearby stars, namely USNO 1200-15039207 (Rmag=12.9) and USNO 1200-15046396 (Rmag=12.7), located 140 arcsec west and 96 arcsec southeast of the source, respectively. No further absolute photometric calibration has been applied on these data. The extracted light curve can be found under: https://sites.google.com/site/astrofridaysmeetings/paratereseis/grb This message is quotable in publications. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17932 SUBJECT: Fermi Gamma-ray Burst Monitor triggers bn150615791 and bn150615798 are not GRBs DATE: 15/06/15 22:36:41 GMT FROM: George A. Younes at George Washington U G. Younes (GWU) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers bn150615791 and bn150615798 at 18:59:01.20 UT and 19:09:42.11 UT on 15 June 2015, respectively, tentatively classified as GRBs, are in fact not due to GRBs. These triggers are due to V404 Cyg (Barthelmy et al. 2015, GCN 17929)." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17933 SUBJECT: V404 Cyg: Swift/UVOT Detection DATE: 15/06/16 15:01:12 GMT FROM: Samantha Oates at MSSL S. R. Oates (IAA-CSIC/UCL-MSSL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of V404 Cyg 184 s after the BAT trigger (Barthelmy et al., GCN Circ. 17929). A source consistent with the XRT position is detected in the initial UVOT exposures. The white filter is approximately constant for the first 600s after the trigger, but a slight increase in flux is observed in white after this time until observations cease at ~900s. The increase in flux is also observed in the v and b filters. Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (FC) 184 334 147 15.72 +/- 0.02 white 875 919 44 15.34 +/- 0.03 v 673 693 19 14.58 +/- 0.07 v 848 867 19 14.22 +/- 0.06 b 599 619 19 16.17 +/- 0.08 b 773 793 19 15.78 +/- 0.07 u (FC) 342 591 246 16.13 +/- 0.04 u 748 768 20 16.06 +/- 0.11 w1 722 742 19 > 17.66 m2 698 717 19 > 17.45 w2 649 843 39 > 18.37 The magnitudes in the table are not corrected for the large Galactic extinction due to the reddening of E(B-V) = 2.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17934 SUBJECT: Fermi GBM trigger 150616594 is not a GRB DATE: 15/06/16 16:45:35 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) and B. Mailyan (UAH) report on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 456156966/150616594 at 14:16:03.39 UT on the 16th of June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17935 SUBJECT: Fermi GBM trigger 150616734 is not a GRB DATE: 15/06/16 19:05:08 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 150616734/456169002 at 17:36:39.42 UT on the 16 of June 2015, tentatively classified as GRB, is in fact not due to GRB. This trigger is due to V404 Cyg.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17938 SUBJECT: Konus-Wind observation of Galactic transient V404 Cyg in outburst DATE: 15/06/17 10:40:37 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, report: On June 15, 2015 Konus-Wind detected a hard X-ray transient activity lasting from ~65300 s UT (18:08:20) to ~69000 s UT (19:10:00). Taking into account the proximity of this burst to the Swift/BAT trigger due to V404 Cygni (T0=T0(BAT)=18:31:38 UT; Barthelmy et al., GCN 17929), two subsequent Fermi/GBM triggers due to the same source (Younes, GCN 17932), and consistency of the KW ecliptic latitude response with the position of V404 Cygni we suggest that KW observed the ~1 hour-long flare from this Galactic black hole candidate. The KW light curve recorded in the waiting mode shows a multi-peaked complex which started at ~T0(BAT)-1400 s, peaked at ~T0(BAT)+1640 s, and lasted until ~T0+2300 s. The emission is visible in the instrument's G1 (20-75 keV) and G2 (75-300 keV) bands. The K-W light curve is available at http://www.ioffe.rssi.ru/LEA/V404_Cyg/KW150615_V404_Cyg/ As observed by Konus-Wind, the burst had a fluence of (1.8 ± 0.1)x10^-4 erg/cm2, and a 2.944-s peak flux, measured from ~T0+1642 s, of (2.3 ± 0.4)x10^-7 erg/cm2/s (both in the 20 - 1200 keV energy range). Modeling the 3-channel time-integrated spectrum (from T0-1394.283 s to T0+2315.157 s) by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.28 ± 0.16, and Ep = 122 ± 9 keV. Assuming the distance 2.4 kpc (Miller-Jones et al. 2009) the energy release in the flare is E ~ 8.9x10^40 erg, and the peak luminosity L is ~1.1x10^38 erg/s. Further KW observations of the activity of the source will be reported (there are at lest two episodes detected by the instrument on June 16, 2015). All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17940 SUBJECT: V404 Cyg outburst (Swift trigger 643949 ): TSHAO optical observations DATE: 15/06/17 14:52:17 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the V404 Cyg outburst detected by BAT/Swift (Barthelmy et al., GCN 17929), GBM/Fermi (Younes, GCN 17932; Jenke GCN 17935), and Konus-Wind (Golenetskiiet al., GCN 17938) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. Observations started on June, 15 (UT) 18:50:44 and continued on June 16. We obtained several images in R-filter. The V404 Cyg optical outburst reported early (Gazeas et al, GCN 17931; Oates GCN 17933) is clearly visible. The V404 Cyg is overexposed in our initial images but can be recovered with more detailed analysis. Preliminary light curve of the V404 Cyg can be found in http://grb.rssi.ru/V404_Cyg/v404_20150615_lc.png Photometry is based on following USNO-B1.0 stars ID R2 1238-0434779 13.52 1238-0434864 14.12 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17943 SUBJECT: IBAS trigger 7015 is not a GRB DATE: 15/06/18 00:36:10 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), E.Bozzo, C.Ferrigno (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: The IBAS trigger n. 7015 at 00:08:44 of June 18, 2015 is not due do a GRB. It is due to the source V404 Cyg. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17944 SUBJECT: Swift Trigger 644520 is V404 Cyg DATE: 15/06/18 01:00:29 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 00:44:05 UT, the Swift Burst Alert Telescope (BAT) triggered and located V404 Cyg. Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 306.012, +33.867 which is RA(J2000) = 20h 24m 03s Dec(J2000) = +33d 52' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 50 sec. The peak count rate was ~1300 counts/sec (15-350 keV), at ~20 sec after the trigger. The XRT began observing the field at 00:45:12.7 UT, 67.7 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 306.0163, 33.8645 which is equivalent to: RA(J2000) = +20h 24m 3.91s Dec(J2000) = +33d 51' 52.2" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This position is 4.8 arcseconds from a known X-ray source: 1SXPS J202404.2+335155. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.0183 +/- 0.0015 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ202404.2%2B335155 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 3.15e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 seconds after the BAT trigger. We detect V404 Cyg with a white magnitude of 15.54 +- 0.14. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17945 SUBJECT: Swift Trigger 644596 is V404 Cyg DATE: 15/06/18 09:08:53 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst J. R. Cummings (NASA/UMBC), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 08:52:26 UT, the Swift Burst Alert Telescope (BAT) triggered and located V404 Cyg (trigger=644596) again, with a somewhat higher flux level than the previous triggers. Swift did not slew promptly to the source due to an observing constraint. The BAT on-board calculated location is RA, Dec 305.998, +33.864 which is RA(J2000) = 20h 24m 00s Dec(J2000) = +33d 51' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed some weak variability. The peak count rate was ~1637 counts/sec (15-350 keV), at ~5 sec after the trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17946 SUBJECT: Swift triggers again on V404 Cyg DATE: 15/06/18 13:30:43 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 13:09:20 UT, the Swift Burst Alert Telescope (BAT) triggered and located again V404 Cyg (trigger=644627) (GCNs 17929, 17944, and 17945). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 306.014, +33.869, which is RA(J2000) = 20h 24m 03s Dec(J2000) = +33d 52' 09" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several slightly overlapping peaks with a duration of about 15 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 13:10:06.9 UT, 46.5 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 306.0154, 33.8666 which is equivalent to: RA(J2000) = +20h 24m 3.70s Dec(J2000) = +33d 51' 59.8" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This position is 8.1 arcseconds from a known X-ray source: 1SXPS J202404.2+335155. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.0183 +/- 0.0015 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ202404.2%2B335155 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.26e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 56 seconds after the BAT trigger. V404 Cyg is detected with a white magnitude of 15.0 +/- 0.2. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17948 SUBJECT: V404 Cyg: Fermi GBM observations DATE: 15/06/19 22:19:19 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH), P. Jenke (UAH), B. Mailyan (UAH), G. Younes (GWU), and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: "The Fermi Gamma-Ray Burst Monitor has triggered multiple times on the current outburst of V404 Cyg. These triggers have all been misclassified as GRBs by the flight software. A list of V404 Cyg triggers up to now is listed below. It is likely that there will be more triggers from this source as long as it remains active and we will not issue circulars for these triggers. We will populate our online trigger catalog with the correct classification as soon as possible. The online trigger catalog is updated automatically by the HEASARC once per day. A list of V404 Cyg triggers can be found by searching for the 'TRANSNT' trigger type and confirming the location. The catalog can be browsed at: http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigtrig.html Triggers that our duty scientist classifies as GRBs are followed by GCN notices with a final human-in-loop localization with a latency of 30 minutes to a few hours after the trigger. Triggers that are not classified by a human as GRBs are not followed by final position GCN notices. Triggers from V404 Cyg to date: 150619774/456431653 150619580/456414880 150619570/456414027 150619561/456413265 150619554/456412636 150619427/456401723 150619420/456401105 150619352/456395199 150619342/456394328 150619317/456392148 150619309/456391510 150619301/456390804 150619242/456385736 150619224/456384186 150619173/456379743 150619165/456379080 150618834/456350498 150618763/456344362 150618710/456339724 150616921/456185211 150616855/456179459 150616734/456169002 150615798/456088185 150615791/456087544" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17949 SUBJECT: Trigger 645176: Swift detection of V404 Cyg DATE: 15/06/20 13:58:58 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. M. Chester (PSU), D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 13:28:26 UT, the Swift Burst Alert Telescope (BAT) triggered and located V 404 Cyg (trigger=645176). Swift did not slew to this new trigger because the merit value of this new trigger was less than the previous trigger. The BAT on-board calculated location is RA, Dec 306.002, +33.859, which is RA(J2000) = 20h 24m 00s Dec(J2000) = +33d 51' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, there is nothing significant in the real-time light curve. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17950 SUBJECT: Swift Trigger 645340: a possible GRB DATE: 15/06/21 12:01:59 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 11:28:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located either Sco X-1 or a source near Sco X-1. Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 245.071, -15.691 which is RA(J2000) = 16h 20m 17s Dec(J2000) = -15d 41' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT position is 6.1 arcmin from Sco X-1. This was a 64 s image trigger with significance of 17.7 sigma. As is usual with an image trigger, the available BAT light curve shows no significant structure. The source centroided on by the XRT is Sco X-1. This is, however, 363 arcsec from the BAT position, and thus outside the BAT error circle. We cannot determine at this time whether there is a new X-ray source within the BAT error circle. UVOT took a finding chart exposure of 150 seconds with the White filter starting 185 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the BAT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. No correction has been made for the expected extinction corresponding to E(B-V) of 0.38. We await the full downlinked dataset to make a more definitive statement on the nature of this trigger. Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17951 SUBJECT: Swift Trigger 645340 was Sco X-1 DATE: 15/06/22 00:41:27 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) reports on behalf of the Swift Team: Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT trigger 645340 (Marshall et al., GCN Circ. 17950). The BAT ground-calculated position is RA, Dec = 244.988, -15.638 deg which is RA(J2000) = 16h 19m 57.1s Dec(J2000) = -15d 38' 15.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). This position is consistent with the location of Sco X-1 (with separation of 0.51 arcmin). The BAT spectrum of this source is quite soft, which is consistent with the spectral feature of Sco X-1 (Baumgartner et al. 2013; http://swift.gsfc.nasa.gov/results/bs70mon/SWIFT_J1620.1-1539) Therefore, we confirm that BAT trigger 645340 (GCN #17950) was due to Sco X-1 and not to a new source. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/645340/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17955 SUBJECT: Fermi Gamma-ray Burst Monitor triggers bn150622899 and bn150623043 are not GRBs DATE: 15/06/23 04:10:31 GMT FROM: George A. Younes at George Washington U G. Younes (GWU) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers bn150622899 and bn150623043 at 21:34:53.08 UT and 01:01:17.48 UT on 22 and 23 June 2015, respectively, tentatively classified as GRBs, are in fact not due to GRBs. These triggers are due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17956 SUBJECT: V404 Cyg: MASTER Swift, Integral alert observations DATE: 15/06/23 12:56:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, E.Popova, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute Rafael Rebolo, Miquel Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias) D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Carlos Lopez, Claudio Mallamaci and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER-Tunka was pointed to the V404 Cyg 36 sec after notice time , 164 sec after Swift trigger N 643949 (Barthelmy et. al GCN #17929 )time at 2015-06-15 18:34:23 UT. MASTER-Ural was pointed to the V404 Cyg 22 sec after notice time , 150 sec after swift trigger N 643949 (Barthelmy et. al GCN #17929 ) time at 2015-06-15 18:34:09 UT. The 5 MASTER (http://observ.pereplet.ru , Lipunov et al.2010, Advances in Astronomy, vol. 2010, pp. 1-7) robotic twin telescopes every clear night observed V404 Cyg by Integral alerts sending ( Erik Kuulkers, ATel #7695). Site DATE UT Start DATE UT Finish Exp Duration Polarisation Tunka 2015-06-15 18:34:23 2015-06-15 19:33:48 40 1.0 h |- 2 Ural 2015-06-15 18:34:09 2015-06-15 19:42:09 10 1.1 h /\ 3 IAC 2015-06-18 00:09:07 2015-06-18 05:26:19 190 5.2 h |- 4 Tunka 2015-06-18 14:45:47 2015-06-18 19:44:43 96 5.0 h |- 5 Kisl 2015-06-18 18:50:29 2015-06-19 00:34:30 176 5.4 h |- 6 SAAO 2015-06-18 22:19:33 2015-06-19 04:42:30 282 6.5 h \/ 7 Tunka 2015-06-19 14:21:47 2015-06-19 19:12:1 90 4.9 h |- 8 Kisl 2015-06-19 18:08:38 2015-06-19 22:02:20 108 3.1 h |- 9 SAAO 2015-06-19 21:26:05 2015-06-20 04:41:46 318 7.3 h \/ 10 Tunka 2015-06-20 16:07:32 2015-06-20 19:33:50 59 3.5 h |- 11 Kisl 2015-06-20 17:55:38 2015-06-20 20:24:19 36 3.5 h |- 12 SAAO 2015-06-20 21:59:20 2015-06-21 04:43:37 320 6.7 h \/ 13 Tunka 2015-06-21 19:04:51 2015-06-21 19:36:31 26 0.5 h |- 14 SAAO 2015-06-21 21:16:36 2015-06-22 04:43:06 320 7.5 h \/ 15 Kisl 2015-06-21 21:30:56 2015-06-22 00:36:31 78 3.0 h |- 16 SAAO 2015-06-22 21:15:28 2015-06-23 04:43:58 260 7.5 h \/ We have more than 2400 mesuarments now; The preliminary photometry of MASTER-Net telescopes are available at http://master.sai.msu.ru/static/OT/MASTERV404.jpg We see > 8% linear polarisation ( that corresponds to ATEL #7678 , ATEL #7674). We defenitely detect polatizations variability at time scale ~10 minutes. The Ural light curves (upper fig.) VS polarization (below) data are available at http://master.sai.msu.ru/static/v404syg_tu.png The observations are continued. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17957 SUBJECT: Fermi Gamma-ray Burst Monitor triggers that are not GRBs DATE: 15/06/23 22:18:48 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu (MPE) and G. Younes (GWU) report on behalf of the Fermi GBM Team: "The following Fermi Gamma-ray Burst Monitor (GBM) trigger, on 23 June 2015, tentatively classified as GRB, is in fact not due to GRB. This trigger is due to particle activity: 150623.466 at UT 11:10:32.53. The following Fermi Gamma-ray Burst Monitor (GBM) trigger, on 22 June 2015, tentatively classified as GRB, is in fact not due to GRB. This trigger is due to solar activity: 150622.751 at UT 18:01:29.71." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17958 SUBJECT: Trigger 645944: Swift detection of H1745-203 DATE: 15/06/23 22:53:59 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), L. M. Z. Hagen (PSU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 22:42:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located H1745-203 (trigger=645944). Swift did not slew due a higher merit value source being observed. The BAT on-board calculated location is RA, Dec 267.232, -20.395, which is RA(J2000) = 17h 48m 56s Dec(J2000) = -20d 23' 42" with an uncertainty of 4 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 10 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17959 SUBJECT: Swift Trigger 646423 is GS 1354-645 DATE: 15/06/25 14:37:58 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), P. A. Evans (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. G. R. Roegiers (PSU), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 14:15:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GS 1354-645 (trigger=646423). Swift did not slew due to observing constraint. The BAT on-board calculated location is RA, Dec 209.512, -64.734, which is RA(J2000) = 13h 58m 03s Dec(J2000) = -64d 44' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, there is nothing of note in the real-time light curve. Due to an observing constraint, Swift will not slew until T0+61.8 minutes. There will be no XRT or UVOT data until this time. This source is currently in outburst as described in ATel #7612, #7614, #7620, #7637, #7656 and has been observed by Swift with a ToO campaign. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17963 SUBJECT: Trigger 646721: Swift detection of V 404 Cyg DATE: 15/06/26 13:03:00 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 12:49:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located V404 Cyg (trigger=646721). Swift was already observing this location because of a TOO commanded upload. The BAT on-board calculated location is RA, Dec 306.006, +33.868 which is RA(J2000) = 20h 24m 02s Dec(J2000) = +33d 52' 06" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). We are not reporting a light curve due to a loss of a data packet in the TDRSS real-time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17980 SUBJECT: V404 Cyg activity (Swift, Fermi, INTGRAL, KONUS, MAXI detection): optical observations in TSHAO, Khureltogot, and AAO DATE: 15/06/28 11:27:33 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), S. Schmalz (AIP), I. Reva (Fesenkov Astrophysical Institute), R. Inasaridze (AAO), N. Tungalag (Research Center of Astronomy and Geophysics MAS), I. Molotov (KIAM), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We are observing (Mazaeva et al, GCN 17940) the V404 Cyg activity detected by BAT/Swift (Barthelmy et al., GCN 17929), GBM/Fermi (Younes, GCN 17932; Jenke GCN 17935), Konus-Wind (Golenetskiiet al., GCN 17938), MAXI (Negoro et al., ATel #7646), and INTEGRAL (Roque et al., ATel #7693) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory, ORI-40 0.4m telescope of ISON-Khureltogot and AS-32 0.7m telescope of Abastumani observatory. The V404 Cyg optical activity reported by many observatories is clearly visible in our observations on time scale of at least 60 s (time exposures of our observations in R and Clear filters are 60 and 30 s). Preliminary light curves of the V404 Cyg activity in R-band are following: overall light curve obtained till now (no all data still reduced) http://grb.rssi.ru/V404_Cyg/v404_v12.png and zoom of each day since initial Swift trigger (Barthelmy et al., GCN 17929) http://grb.rssi.ru/V404_Cyg/v404_v11a_0d.png http://grb.rssi.ru/V404_Cyg/v404_v11b_1d.png http://grb.rssi.ru/V404_Cyg/v404_v11c_2d.png http://grb.rssi.ru/V404_Cyg/v404_v11d_3d.png http://grb.rssi.ru/V404_Cyg/v404_v11e_6d.png http://grb.rssi.ru/V404_Cyg/v404_v11f_9d.png Photometry is based on following USNO-B1.0 stars ID R2 1238-0434779 13.52 1238-0434864 14.12 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17983 SUBJECT: Fermi Gamma-ray Burst Monitor trigger bn150629779 is not a GRB DATE: 15/06/29 19:46:26 GMT FROM: George A. Younes at George Washington U G. Younes (GWU) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger bn150629779 at 18:41:34.97 UT on 29 June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17984 SUBJECT: Fermi Gamma-ray Burst Monitor Trigger bn150628857 is not a GRB DATE: 15/06/30 16:05:25 GMT FROM: Binbin Zhang at UAH Bin-Bin Zhang (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger bn150628857 at 20:33:39.177 UT on 28 June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17985 SUBJECT: Fermi Gamma-ray Burst Monitor Trigger 150626873 is not a GRB DATE: 15/06/30 16:15:56 GMT FROM: Eric Burns at U of Alabama "The Fermi Gamma-ray Burst Monitor (GBM) trigger 150626873/457045019 at 20:56:56.92 UT on 26 June 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity.†//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17986 SUBJECT: Swift Trigger 647642 is probably not an astrophysical source DATE: 15/07/02 07:19:32 GMT FROM: Kim Page at U.of Leicester P. A. Evans (U Leicester), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 06:59:05 UT, the Swift Burst Alert Telescope (BAT) triggered on a marginal significance peak in an non-rate-triggered image (trigger=647642). Swift slewed immediately to the event. The BAT on-board calculated location is RA, Dec 161.248, +55.989 which is RA(J2000) = 10h 45m 00s Dec(J2000) = +55d 59' 22" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual with an image trigger, the available BAT light curve shows no significant structure. The XRT began observing the field at 07:01:44.1 UT, 158.9 seconds after the BAT trigger. No source was detected in 822 s of promptly downlinked data. UVOT took a finding chart exposure of 145 seconds with the White filter starting 163 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Because this is a marginal significance detection of a peak in a non-rate-triggered image, with no corresponding source in the XRT data, we believe that this is noise fluctuation and not an astrophysical source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17988 SUBJECT: Fermi GBM Observations is no longer triggerin on V404 Cyg DATE: 15/07/02 20:35:38 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) and E. Burns (UAH) report on behalf of Fermi GBM team: On June 15, 18:59:01.20 UTC, Fermi/GBM triggered (G. Younes et al., GCN 17932) on a hard X-ray flare from V404 Cyg. For the next 12 days, GBM triggered 169 times on flares from this source. Many of the triggers arose, not from individual events but from Earth occultation edges of longer events. The last GBM trigger for V404 Cyg occurred on June 27, 23:27:50.54 UTC and we assume that the source has fallen below GBM’s threshold on its return to quiescence. Quarter day integrated Earth occultation (PI C. A. Wilson-Hodge) results show that V404 Cyg reached a maximum flux in the 25-50 keV band of 7.2 crab on June 26 while the source reached a maximum flux in the 100-300 keV band of 5.2 crab on June 19. A list of V404 Cyg triggers can be found in the trigger catalog by searching for the 'TRANSNT' trigger type and confirming the location. The catalog can be browsed at: http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigtrig.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17996 SUBJECT: Fermi Gamma-ray Burst Monitor Trigger bn150705731 is not a GRB DATE: 15/07/06 19:23:35 GMT FROM: George A. Younes at George Washington U G. Younes (GWU) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger bn150705731 at 17:32:00.26 UT on 05 July 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17998 SUBJECT: Trigger 648422: Swift possible detection of a source in NGC4552 DATE: 15/07/09 22:02:08 GMT FROM: Scott Barthelmy at NASA/GSFC A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Y. Lien (GSFC/UMBC), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 21:42:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible source near NGC4552 (trigger=648422). Swift did not slew because of an earth-limb observing constraint. The BAT on-board calculated location is RA, Dec 188.824, +12.672, which is RA(J2000) = 12h 35m 18s Dec(J2000) = +12d 40' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). We note that this is ~9 arcmin NGC 4552, and as such it allows for a lower threshold value not the trigger criteria. As is typical for image triggers, there is nothing significant in the real-time light curve. When the source location comes out of observing constraint (at T+49 minutes), Swift will slew to it and then XRT and UVOT will produce their usual automated data products. And then a refined circular will be issued about the identity and reality of this trigger. Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17999 SUBJECT: Swift Trigger 648422: Swift-XRT observations DATE: 15/07/09 23:25:21 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri, P. D'Avanzo, M.G. Bernardini (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: The XRT began observing the field of the possible transient source near NGC4552 (trigger=648422; Melandri et al., GCN 17998) at 22:38:45.6 UT, 3388.4 seconds after the BAT trigger. No source was detected in 1590 s of promptly downlinked data. Due to the non-detection of a counterpart in the XRT observation, we cannot confirm that this is a real astrophysical source at this time. We await the full downlinked dataset to make a more definitive statement on the nature of this trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18004 SUBJECT: Confirmation that Swift trigger 648422 is not an astrophysical source DATE: 15/07/10 14:48:22 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) reports on behalf of the Swift Team: We conclude that Swift trigger #648422 (Melandri et al., GCN Circ. 17998) was the result of noise fluctuations and is not due to a GRB or other astrophysical event. We have analyzed the BAT data set from T-119 to T+183 sec from the recent telemetry downlinks. We find that there is no sign of significant emission from the trigger location at any point in this interval. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18007 SUBJECT: MASTER OT Detection during Fermi Trigger 458235025 inspection DATE: 15/07/10 20:00:46 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, P.Balanutsa,A.Kuznetsov, E.Popova, D. Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory Rafael Rebolo, Miquel Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB150710.65 130 sec after notice time and 3592 sec after trigger time at 2015-07-10 16:30:13 UT. On our first (180s exposure) set we found OT MASTER J071803.26+644745.0 within FERMI error-box (ra=08 55 31 dec=+48 54 00 r=11.670000). The OT unfiltered magnitude is 14.5m (limit 17.2m). Coordinates OT source (RA, Dec) = 07h 18m 03.26s +64d 47m 45.0s on 2015-07-10.74346 UT. This OT is identical to USNO-B1 star with B2=17.93, R2=17.97, I=17.66; also is a GALEX source (18.863) and a source from SDSS DR10 catalogue of candidate quasars (Brescia+, 2015) . Previous outburst was detected as ASASSN-15bq and classified like UG The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18021 SUBJECT: Fermi GBM trigger 458312518/150711543 is not a GRB DATE: 15/07/12 19:19:49 GMT FROM: Hoi-Fung Yu at MPE Hoi-Fung Yu (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 458312518/150711543 at 13:01:54.13 UT on 11 July 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is accidental." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18023 SUBJECT: Fermi Gamma-ray Burst Monitor triggers that are not GRBs DATE: 15/07/14 15:32:53 GMT FROM: Hoi-Fung Yu at MPE G. Younes (GWU) and H.-F. Yu (MPE) report on behalf of the Fermi GBM Team: "The following Fermi Gamma-ray Burst Monitor (GBM) triggers 150712.535 (12 July 2015, 12:50:53.84 UT), 150713.123 (13 July 2015, 02:57:44.70 UT), 150713.526 (13 July 2015, 12:37:45.28 UT), 150713.951 (13 July 2015, 22:50:00.78 UT), and 150714.116 (14 July 2015, 02:47:26.04 UT), tentatively classified as GRBs, are in fact not due to GRBs. These triggers are due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18024 SUBJECT: Trigger 649113: Swift detection of SGR 1E 1841-045 DATE: 15/07/15 18:30:12 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 18:12:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1E 1841-045 (trigger=649113). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 280.330, -4.930, which is RA(J2000) = 18h 41m 19s Dec(J2000) = -04d 55' 47" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of less than 0.128 sec. The peak count rate was ~8600 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 18:14:13.2 UT, 95.4 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 280.33029, -4.93495 which is equivalent to: RA(J2000) = 18h 41m 19.27s Dec(J2000) = -04d 56' 05.8" with an uncertainty of 3.8 arcseconds (radius, 90% containment). . This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 6.3 arcseconds from that of a known X-ray source: 3XMM J184119.3-045612 in the XMM-NEWTON XMMSSC catalogue. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.71 x 10^22 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 101 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical upper limit has been about 19.6 mag, but this is an unusually crowded field. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18025 SUBJECT: Trigger 649143: Swift detection of AX J1619.4-4945 DATE: 15/07/16 02:40:41 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), J. A. Kennea (PSU), P. Romano (INAF-IASFPA) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 01:54:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located AX J1619.4-4945 (trigger=649143). Swift's slew was delayed by an SAA transit and lack of observability. The BAT on-board calculated location is RA, Dec 244.970, -49.810 which is RA(J2000) = 16h 19m 53s Dec(J2000) = -49d 48' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers, there is nothing significant in the real-time light curve. Although we believe that this is probably the HMXB source AX J1619.4-4945, the marginal significance (6.46 sigma) and distance from the catalog position (5 arcminutes) leave some room for doubt. Confirmation of this detection will require the full downlinked dataset and follow-up observations by XRT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18026 SUBJECT: Fermi GBM triggers bn150715759 and bn150715817 are not due to GRBs DATE: 15/07/16 04:17:59 GMT FROM: George A. Younes at George Washington U G. Younes (GWU) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers bn150715759 and bn150715817 at 18:12:38.09 and 19:36:22.35 UT on 15 July 2015, respectively, tentatively classified as GRBs, are in fact not due to GRBs. These two triggers are due to magnetar 1E 1841-045." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18031 SUBJECT: Swift trigger 649143 is not AX J1619.4-4945 or other astrophysical source DATE: 15/07/17 13:26:37 GMT FROM: Amy Lien at GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. A. Kennea (PSU) P. Romano (INAF-IASFPA) report on behalf of the Swift Team: We conclude that Swift trigger 649143 (Barthelmy, et al., GCN Circ. 18025) was the result of noise fluctuations and is not due to AX J1619.4-4945 or other astrophysical event. We have analyzed the BAT data set from T-119 to T+148 sec from the recent telemetry downlink. We find that there is no sign of significant emission from the trigger location at any point in this interval. XRT observations with 471 seconds of data show a detection of AX J1619.4-4945 at 0.05 c/s, which is consistent with the quiescent flux level of this source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18037 SUBJECT: Swift Trigger 649706: a possible GRB or bright Galactic transient DATE: 15/07/20 14:29:11 GMT FROM: Scott Barthelmy at NASA/GSFC E. Sonbas (NASA/GSFC/Adiyaman Univ.), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. B. Cenko (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), S. L. Gibson (U Leicester), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 14:02:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located possible GRB 150720A (trigger=649706). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 119.582, -28.301, which is RA(J2000) = 07h 58m 20s Dec(J2000) = -28d 18' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image trigger (64-sec), there is nothing significant in the real-time TDRSS light curve. The XRT began observing the field at 14:04:23.7 UT, 134.6 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 119.5810, -28.2623 which is equivalent to: RA(J2000) = 07h 58m 19.45s Dec(J2000) = -28d 15' 44.2" with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 139 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 5.72 x 10^21 cm^-2 (Willingale et al. 2013). The initial flux in the 0.1 s image was 2.93e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 142 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The event is near the galactic plane (l=245, b=0.5) and has a rapid decrease in X-ray afterglow. Also, it was a faint image trigger in BAT but very bright in X-rays. We can not rule out that the source is a galactic transient instead of a gamma-ray burst. Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18051 SUBJECT: Trigger 650140: Swift detection of IGR J00291+5934 DATE: 15/07/24 06:11:12 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:23:37 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source consistent with the location of the known source IGR J00291+5934 (=V1037 Cas) (trigger=650140). Swift could not slew immediately to the burst due to an Earth limb constraint. The BAT on-board calculated location is RA, Dec 7.200, +59.565 which is RA(J2000) = 00h 28m 48s Dec(J2000) = +59d 33' 54" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). No light curve is immediately available for this image trigger. Although this is a marginal significance (6.11 sigma) image trigger, it is likely to be a true detection, based on the close match (2 arcminutes) to the source location and the fact that this source is often seen by BAT. To avoid confusion, we note that this is not GRB 150724A, which occurred shortly after this detection. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18053 SUBJECT: SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit DATE: 15/07/24 08:42:41 GMT FROM: Moskvitin Alexander at SAO RAS I. V. Sokolov (TF INASAN, Russia), E. L. Entina (MSU, Russia), A. S. Moskvitin (SAO RAS, Russia) report on behalf of a larger collaboration. The field of SGR 1E 1841-045 (Swift trigger 649113, Barthelmy et al., GCNC 18024) was observed with the 2-meter telescope Zeiss-2000 at the Terskol peak on the July, 15. The observations started since 2.2 hours after the trigger. We can not find any object inside the XRT error circle in the stacked 40 min. frame down to the limiting magnitude R_lim = 21.4. Photometry is was based on nearby USNO-B1 stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18056 SUBJECT: IGR J00291+5934: Swift-BAT refined analysis DATE: 15/07/24 14:18:11 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+603 sec from recent telemetry downlinks, we report further analysis of the trigger #650140 on IGR J00291+5934 (Cummings, et al., GCN Circ. 18051). The BAT ground-calculated position is RA, Dec = 7.221, 59.546 deg, which is RA(J2000) = 00h 28m 53.0s Dec(J2000) = +59d 32' 44.3" with an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 70%. The mask-weighted light curve shows constant low-level emission (0.03 cnts/cm2/sec in the 15-350 keV band)) starting at ~T-118, when the source location came into the BAT FoV during a pre-planned slew, out to at least T+603 sec when we no long have data. The time-averaged spectrum from T+0 to T+603 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.01 +- 0.32. The fluence (over this window of data) in the 15-150 keV band is 1.4 +- 0.3 x 10^-6 erg/cm2. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/650140/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18058 SUBJECT: Swift IGR J00291+5934: MASTER Optical flare detection DATE: 15/07/24 16:46:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs ---------- Forwarded message ---------- Date: Fri, 24 Jul 2015 19:44:33 +0300 (MSK) From: Lipunov V.M. To: gcncirc@capella.gsfc.nasa.gov Subject: IGR J00291+5934: Optical flare detection R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa,A.Kuznetsov,D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in IAC was pointed to the IGR J00291+5934 (Cummings et al., GCN 18051) 24 sec after notice time and 1103 sec after trigger time at 2015-07-24 05:42:03 UT. On our first (180s exposure) set we haven`t found optical transient within SWIFT error-box. The 5-sigma upper limit has been about 17.2 mag MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the IGR J00291+5934 Swift Trigger 35223 sec after notice time and 36279 sec after trigger time at 2015-07-24 15:28:16 UT. On our first (180s exposure) set we found 1 optical transient within Swift error-box ~ 17.5 unfileterd mag (CCD is red, m=0.2B+0.8R with respect to USNO B ). The 5-sigma upper limit has been about 19.4 mag . The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18060 SUBJECT: Correction to GCN 18059: Parameterisation of Swift-XRT light curve DATE: 15/07/24 18:39:51 GMT FROM: Kim Page at U.of Leicester K.L. Page, A.P. Beardmore (U. Leicester) and J.L. Racusin (NASA/GSFC) report on behalf of the Swift-XRT team: The description of the XRT light curve given in GCN Circ. 18059 was incorrect. Following significant flaring activity during the first 1.3 ks of data, the light curve from T0+4.7 ks to 24.0 ks remains approximately constant with a mean count rate of 0.04 ct/sec (not 2.2 ct/sec as previously stated). We apologise for any confusion. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18061 SUBJECT: Trigger 650221: Swift detection of a IGR J00291+5934 DATE: 15/07/25 02:32:31 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 02:12:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located IGR J00291+5934 (trigger=650221). Swift slewed immediately to the source location. The BAT on-board calculated location is RA, Dec 7.256, +59.596 which is RA(J2000) = 00h 29m 01s Dec(J2000) = +59d 35' 45" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows weak and complex structure with a duration of about 20 sec. The peak count rate was ~1281 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 02:14:04.4 UT, 119.5 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 7.2571, 59.5736 which is equivalent to: RA(J2000) = +00h 29m 1.70s Dec(J2000) = +59d 34' 25.0" with an uncertainty of 6.1 arcseconds (radius, 90% containment). This position is 12.6 arcseconds from a known X-ray source: 1SXPS J002903.1+593418. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 1.740 +/- 0.037 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ002903.1%2B593418 for details of these previous observations. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 0.1 s image was 1.57e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 128 seconds after the BAT trigger. There is a candidate counterpart in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 00:29:03.06 = 7.26274 DEC(J2000) = +59:34:19.2 = 59.57199 with a 90%-confidence error radius of about 0.62 arc sec. This position is 11.8 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.49 with a 1-sigma error of about 0.14. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18063 SUBJECT: Fermi GBM trigger 150725291 is not a GRB DATE: 15/07/25 11:16:20 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 459500385/150725291 at 06:59:41.57 UT on the 25th of July 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18064 SUBJECT: Swift Trigger 650221 / IGR J00291+5934: MASTER-IAC OT observations DATE: 15/07/25 13:09:58 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa,A.Kuznetsov,D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in IAC Teide Observatory (Tenerife) was pointed to the Swift Trigger 650221/IGR J00291+5934 (Barthelmy et al., GCN 18061) 30 sec after notice time and 88 sec after trigger time at 2015-07-25 02:13:33 UT. On our first (20s exposure) coadd set we clearly see IGR J00291+5934 Optical Counterpart with 17.40+-0.10 unfiltered MASTER instrumental magnitude. The limit is 18.1. We have 131 images in two tube up to 2015-07-25 05:43:08 UT. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18067 SUBJECT: IGR J00291+5934, Swift-BAT refined analysis DATE: 15/07/25 19:03:36 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-225 to T+977 sec from the recent telemetry downlink, we report further analysis of trigger #650221 on IGR J00291+5934 (Barthelmy, et al., GCN Circ. 18061). The BAT ground-calculated position is RA, Dec = 7.269, 59.583 deg which is RA(J2000) = 00h 29m 04.6s Dec(J2000) = 59d 34' 59" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 32%. The mask-weighted lightcurve shows a single peak about 17 seconds long on top of a much weaker variable emission over the entire observation. The 20-second peak was much softer than the ongoing emission. The time-averaged spectrum from T-225 to T+977 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 3.0 +- 0.6. The fluence in the 15-150 keV band was (1.4 +- 0.6) x 10^-06 erg/cm^2. The time-averaged spectrum from T-1.6 to T+16.6 sec is also best fit by a simple power-law model. The power law index of the time-averaged spectrum is 5.5 +- 1.1. The fluence during that interval was (2.4 +- 0.5) x 10^-07 erg/cm^2. The 1-sec peak photon flux measured from T+20.93 sec in the 15-150 keV band was 0.7 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/650221/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18070 SUBJECT: Swift 650221/IGR J00291+5934: Liverpool Telescope observations DATE: 15/07/26 06:55:38 GMT FROM: Drejc Kopac at Math Phys U,Slovenia D. Kopac (U Ljubljana), C. Guidorzi (U Ferrara), C.G. Mundell (U Bath), I.A. Steele (LJMU), A. Gomboc (U Ljubljana), on behalf of a large collaboration report: The 2-m Liverpool Telescope automatically began observing Swift Trigger 650221/IGR J00291+5934 (Barthelmy et al., GCN 18061) with RINGO3 polarimeter, starting 5 minutes post BAT trigger. Observations continued for 2 hours. At the position consistent with Fox & Kulkarni 2004 (ATel #354), and D'Avanzo et al. 2007 (A&A, 472, 881), we clearly detect the optical counterpart. The estimated magnitude is R = 18.07 +- 0.03 at 36.4 minutes post trigger, calibrated against nearby USNO-B1.0 stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18071 SUBJECT: Swift Trigger 650408 is not a burst DATE: 15/07/27 01:49:56 GMT FROM: David Palmer at LANL K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: The recent Swift trigger, #650408, is a misidentification of Sco X-1, due to a pointing error. This is not an interesting astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18107 SUBJECT: Fermi GBM triggers 150730606 150731173 and 150801590 are not due to GRBs DATE: 15/08/02 02:28:30 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers 150730606/459959529, at 14:32:05.36 UT on the 30th of July 2015, 150731173/4600008527 at 04:08:43.43 UT on the 31st of July 2015, and 150801590/460130970 at 14:09:26.41 UT on the 1st of August 2015, tentatively classified as GRBs, are in fact not due to GRBs. These triggers are due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18114 SUBJECT: Fermi GBM trigger 150805556 is not a GRB DATE: 15/08/05 14:54:25 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 460473677/150805556 at 13:21:13.51 UT on the 5th of August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18116 SUBJECT: Fermi GBM trigger 150806450 is not a GRB DATE: 15/08/06 11:56:46 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 460550875/150806450 at 10:47:51.42 UT on the 6th of August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18117 SUBJECT: Fermi GBM trigger 150807969 is not a GRB DATE: 15/08/08 00:11:53 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 460682117/150807969 at 23:15:13.61 UT on the 7th of August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18136 SUBJECT: Swift Trigger 652046 is probably not a GRB DATE: 15/08/13 05:19:13 GMT FROM: David Palmer at LANL A. D'Ai (INAF-IASFPA), N. Gehrels (NASA/GSFC), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team: At 04:54:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible, but unlikely, GRB (trigger=652046). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 216.661, -7.541 which is RA(J2000) = 14h 26m 39s Dec(J2000) = -07d 32' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single high time bin with a duration of about 0.128 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~0.1 sec after the trigger. The XRT began observing the field at 04:55:25.5 UT, 57.3 seconds after the BAT trigger. No source was detected in 955 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 60 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Due to the marginal image significance of this event (6.5 sigma), and the lack of an X-ray detection, we believe that this is probably a statistical fluctuation rather than an astrophysical event. Determination of the reality of this event will require the full downlinked dataset. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18142 SUBJECT: Fermi GBM Trigger 150815694 is not a GRB DATE: 15/08/15 23:17:03 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 461349522/150815694 at 16:38:38.71 UT on the 15th of August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to an accidental trigger." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18185 SUBJECT: Swift Trigger 652824: Is most likely a noise fluctuation in the direction of M31 DATE: 15/08/21 02:51:09 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), J. A. Kennea (PSU), A. Melandri (INAF-OAB) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 02:17:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located a noise fluctuation in the direction of M31 (trigger=652824). There was no immediate slew because of an observing constraint. The BAT on-board calculated location is RA, Dec 10.241, +41.081, which is RA(J2000) = 00h 40m 58s Dec(J2000) = +41d 04' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (7 min), there is nothing significant in the real-time TDRSS light curve. This highly marginal image trigger (6.04 sigma) had a nominal direction in the vicinity of M31, and so the onboard software alerted the ground and requested Swift to make follow-up observations to confirm or refute the existence of an astrophysical source. However, due to the observing constraint, Swift will not able to follow up on the trigger until around 03:30 UT. Based on past experience with marginal detection follow-ups, it is most likely that this is a noise fluctuation rather than an astrophysical source. A final determination of the reality of this source will require the XRT follow-up observations, and analysis of the full downlinked data. We further caution that it is likely that XRT will find multiple unrelated source in its FOV due to the location in M31. If so it will not necessarily be the case that any of these are correlated with the image trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18188 SUBJECT: Swift Trigger 652824 is due to noise DATE: 15/08/21 12:42:41 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) on behalf of the Swift-BAT team: Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report that trigger #652824 (UT=02:17:28) was due to noise in the image and the lower trigger threshold level used for regions on the sky that correlate with known sources or galaxies (M31 in this case). This trigger is not anything astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18204 SUBJECT: Fermi GBM trigger 150826536 is not a GRB DATE: 15/08/26 18:03:50 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (INFN Bari) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 462286333/150826536 at 12:52:09.54 UT on 26 August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18206 SUBJECT: Fermi GBM trigger 150827524 is not a GRB DATE: 15/08/28 13:23:39 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 462371689/150827524 at 12:34:45.73 UT on the 27 August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a particle event." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18207 SUBJECT: Fermi GBM trigger 150828520 is not a GRB DATE: 15/08/28 20:34:50 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 462457770/150828520 at 12:29:26.76 UT on the 28 August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a particle event." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18208 SUBJECT: Fermi GBM trigger 150829183 is not a GRB DATE: 15/08/30 13:56:27 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 462515035/150829183 at 04:23:51.76 UT on the 29 August 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a particle event." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18231 SUBJECT: ANTARES neutrino detection and possible Swift X-ray counterpart DATE: 15/09/03 11:43:31 GMT FROM: Phil Evans at U of Leicester D. Dornic (CPPM), S. Basa (LAM), P.A. Evans (U. Leicester), J.A. Kennea (PSU), J.P. Osborne (U. Leicester) and V. Lipunov (MSU) report on behalf of the ANTARES Collaboration, the Swift-XRT team and MASTER team: September 1st, 2015, at 07:38:25 UT, ANTARES has detected a bright neutrino at a location of: RA(J2000) = 16h 25m 42s DEC (J2000) = -27d 23m 24s with an uncertainty of 18 arcmin (radius, 50% containment) A target of opportunity alert has been sent immediately to Swift. The XRT onboard Swift followed the ANTARES error box 10 hours after the neutrino detection. An uncatalogued X-ray source has been detected above the limit of RASS, with the flux varying between 5e-13 and 1.4e-12 erg cm^-2 s^-1 (0.3-10 keV), at location: RA(J2000) = 16h 26m 2.12s DEC (J2000) = -27d 18m 14.8s with an uncertainty of 2.4 arcsec (radius, 90% containment). The detected X-ray source seems to be variable. By contrast no transient source in the visible domain with MASTER SAAO has been observed so far until the magnitude 18.5 with a galactic extinction of 2 (Schlegel et al). Further Swift observations have been planned. We encourage strongly further multi-wavelength observations to identify this X-ray source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18236 SUBJECT: ANTARES neutrino detection: Optical/NIR spectroscopy of the Swift/XRT counterpart candidate from NOT DATE: 15/09/04 12:50:00 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), H. Korhonen (U. Turku, NBI), M.I. Andersen (DARK/NBI), J.P.U. Fynbo (DARK/NBI), S. Schulze (PUC, MAS), Z. Cano (U. Iceland), D. Xu (NAOC/CAS), N.R. Tanvir (U. Leicester), D. Watson (DARK/NBI), D. Malesani (DARK/NBI), J. Hjorth (DARK/NBI), A.A. Djupvik (NOT) report on behalf of a larger collaboration: We observed the star USNO-B1.0 0626-0501169, associated with the X-ray emission detected by Swift, within the error box of the high-energy neutrino detected by ANTARES (Dornic et al. 18231, ATel 7987, Smartt et al. ATel 7992), with the 2.5 m NOT telescope at La Palma (Spain). Our observation consisted of 3x400 s spectra with the FIES high-resolution spectrograph in the visible, and 4x120 s spectra with NOTCam in the near-infrared K-band. The FIES spectra were obtained at a resolution of R = 25000 and covered the range between 3700 and 7100 AA, although good S/N is only obtained above 4500 AA. The mean observing epoch was the 3rd September 2015 at 21:45 UT (2.59 days after the neutrino detection), and observation was performed at an airmass of 3. Reduction of the NIR data is still ongoing. The visible spectrum shows a red continuum with multiple absorption features as well as hydrogen Balmer lines in emission. Emission lines of H-alpha and H-beta are resolved, having a FWHM of 75 km/s, and equivalent widths of -1.9 and -1.0 AA, respectively. We detect no emission from HeI or [SII]. The spectrum shows broad and strong absorption due to NaID with a combined equivalent width of 7.1 AA. Detection of a strong absorption at 6708 AA seems to indicate the presence of Li in the object. There is no convincing evidence of molecular bands. All this points to USNO-B1.0 0626-0501169 being a young accreting G-K star, undergoing a flaring episode that produced the X-ray emission. We also note that this object is close to the nearby Rho Ophiuchi star forming region, being probably associated with it. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18239 SUBJECT: ANTARES neutrino detection and Swift/XRT counterpart: GMG observation DATE: 15/09/04 19:02:05 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, W. Yi, C. Wang, and J.-M. Bai (YNAO) report: We observed the star which is located at the position provided by Swift observation for the suggestion of X-ray counterpart of ANTARES neutrino detection (Dornic et al., GCN 18231, de Ugarte Postigo et al., GCN 18236) with the 2.4-meter GMG optical telescope of Yunnan Observatories. Observations began from 12:34:40 UT, Sep. 4, 2015. Under the poor observational condition, we obtained a spectrum covered effective wavelength range between 5500A and 9000A. We preliminarily checked the spectrum, and clearly identified some absorption lines (e.g., strong Na D line) and H alpha emission line. Further careful analysis is ongoing. We thank P. Evans for the information of X-ray observation. We also thank S. Basa, P. D'avanzo, J.-S. Huang, Y.-Z. Fan, D. Xu, and F. Yuan for their discussion. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18240 SUBJECT: ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate DATE: 15/09/04 19:54:20 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D. Dornic (CPPM), V.Lipunov (Lomonosov MSU), S. Basa (LAM), P. A. Evans (U. Leicester), J. A. Kennea (PSU), E.Gorbovskoy and N. Tyurina (Lomonosov MSU), D. Buckley (SAAO), R. Rebolo (IAC) MASTER-SAAO robotic telescope (MASTER­Net: http://observ.pereplet.ru) located in Sutherland received Antares neutrino alert at 2015-09-01 07:38:24.99UT (sunrise) in 16s after trigger time. So and we start observations at nearest available time. MASTER-SAAO automatically started Inspect  survey on the Antares neutrino Alert150901.32 error­box (ra=16 25 42 dec=­27 23 24 r=1.726600) 35107 sec after notice time and 35123 sec after trigger time (2015-09-01 07:38:24.99, sunrise) at 2015­09­01 17:23:48 UT. Observations were up to 2015-09-01 20:25:18 (very cloudy) . MASTER auto-detection system didn’t find any real transient inside the neutrino error box, the unfiltered optical limit on single images is 18.5-19.8 (180s), the sum limit is 20.6 (540s). Observations were continuing on 2015-09-03 17:13:59 (sunset) up to 2015-09-03 21:21:59 (the weather disappeared). We observed in parallel MASTER twin tubes in different filters BV, RI.  The optical limit in B filter on single images was m_B_lim=19.1 (180s), 19.6 on sum (540s) in V filter: m_V_lim=19.3(180s), 19.9 on the sum(540s). The optical limit n R is m_R_lim=18.4-19.0 on single images(60-180s), m_R_lim=19.7-20.3 on sum (540s-1800s). The limit in I was m_I_lim=17.5-18.0 on single images(180s), 18.5 on sum (540s). MASTER-IAC robotic telescope automatically started Inspect observations on 2015-09-01 21:02:44, observed up to 2015-09-01 21:17:34, unfiltered  (W=0.2B+0.8R, USNOB1 calibrated) limit m_lim=18.7-19.2 (180s exposition), 19.8(540s). Observations were continuing in B and V on 2015-09-03 20:08:40 up to 2015-09-03 22:09:12 with limit up to 19.8 in B(180s) and 18.6 in V (180s). No optical transient inside the neutrino error box. The Swift location 16h 26m 02.1s -27d 18m 14s  is difficult for observations from Nothern hemisphere (MASTER-Kislovodsk, -Tunka, -Ural, -Amur). It can be observed at sunset near the horizon. MASTER-Kislovodsk: 02 of Sept there was rain at this observatory at sunset. MASTER-Kislovodsk robotic telescope automatically started Inspect survey on Antares Alert Alert150901.32 on 2015-09-03 16:39:11 UT, at sunset (Object: Altitude: 14.85, Sun: Altitude: -10.65), and were continuing up to 2015-09-03 18:04:47 when the objects’ set. The first hour we have 7  of 30-s expositions  with bad weather condition, the optical  limit in V is 12.0-14.1. Unfiltered observations  starts from 2015-09-03 17:21:39 (Object’s Altitude: 11.01)with optical limit 17.8 on single images (60s expositions), 18.4 on sum (180s). No optical transients detected by MASTER auto-detection system inside ANTARES error-box. MASTER-Tunka robotic telescope started observations of this alert at sunset at 2015-09-03 12:40:59. The Object’s Altitude was 6.86 , the Sun: Altitude: -8.12. Very close to horizon, the object goes under it, 16 expositions of 60s in V,R , no OT inside ANTARES error-box.. MASTER-SAAO optical light curve of bright star USNO-B1.0 0626-0501169 inside Swift XRT error box   in B,V,R and I bands (top diagram) and color diagram (bottom)  represented here: http://master.sai.msu.ru/static/master_antares_alert_150901.png The source is stable in all four band as well as its color. The average color is: B-V = 0.93 +- 0.06 R-I  = 1.07 +- 0.03 A few words about association USNO-B1.0 0626-0501169 and X-ray Swift source (Dornic et al. GCN 18231, ATel #7987 ). Following Swift XRT observation the X-ray flux is changing from 5e-13 to 4e-12 erg/cm2/s (in 0.3-10keV). Full optical flux in MASTER system calibrates as: 15 mag correspond 6.4 10-12 erg/sm2/s . MASTER-SAAO observations of USNO-B1.0 0626-0501169 in January, May and September 2015 show that unfiltered magnitude is m (unfiltered) = 12.36 +-0.03 (Jan); 12.32+- 0.03(May) and 12.32+-0.04 (Sep). Thus it can be argued that the brightness of the star has not changed by more than 3%. Since the X-ray emission occurs near the stellar photosphere, so due to the heating effect of its brightness should slightly increase. The observed brightness of the star persistence restricts the change in X-ray flux in September compared with a May and January: F_x/ F_opt < 3 %. Consequently, F_x < 7 e-11 erg/s. This means that the X-ray heating can not cause optical variability more than 0.003 magnitude. It seems the X-ray is result of the X-ray flare activity of the star (de Ugarte Postigo et al. GCN 18236, ATel #7994; Smartt et al. ATel 7992; Dichiara et al. ATel#7993 ). There is Globular Cluster M4 (NGC621) with millisecond pulsar (Lyne et al., 1988, Nature, V.332, 45-47) and possible massive (~10e3 Solar Mass) black hole inside ANTARES alert 3-sigma error box (the MASTER images of the Antares error box is available at http://master.sai.msu.ru/static/Antares_alert_Image.jpeg By the way there is star Antares (1.3 degrees from center ANTARES error box, but outside! ). So, we propose M4 (with relativistic objects inside) is the possible source of the neutrino, which created after cosmic partical acceleration. The follow up millisecond pulsars observations request. The message may be cited.//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18241 SUBJECT: ANTARES neutrino detection: CAHA photometry & spectroscopy of the Swift source DATE: 15/09/04 21:58:21 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A.J. Castro-Tirado (IAA-CSIC, ISA-UMA), D. Galadí-Enríquez, F. Hoyos, A. Guijarro (CAHA), R. Sánchez-Ramírez, M. Fernández, J. C. Tello, S. Jeong (IAA-CSIC) and J. Maíz-Apellániz (CAB/CSIC-INTA), on behalf of a larger collaboration, report: Following the detection of a posible counterpart to the neutrino ANTARES source by Swift (Dornic et al. GCNC 18231, ATel 7987), we conducted optical monitoring and spectroscopic observations with the 2.2m (+BUSCA) and 3.5m (+TWIN) telescopes at the German-Spanish Calar Alto Observatory (Spain), under non-optimal conditions (airmass 3), starting on Sep 3 at 20:07 UT (2.52 days post ANTARES detection) of the R=12.6 star USNO-B1.0 0626-0501169 (probably a G/K-type star, Smartt et al. ATel 7992). Marginal variability in the B-band is seen in the BUSCA data (6 x 150s exposures). And the TWIN optical spectrum (2 x 300s) in the range 3850-4930 A and 5500-7320 A reveals H-alpha and H-beta in emission as well as other absorption features (e.g. NaI D1+D2), confirming its association to the X-ray source, in agreement with the findings reported by de Ugarte Postigo et al. (GCNC 18236) and Mao et al. (GCN 18239). The non-detection of HeI and the H-lines EWs < 5 A rules out a classical T Tauri star as the counterpart but a weak-line T Tauri star (likely G-type) cannot be excluded. If the X-ray emission is the tail a superflare arising from a young stellar object such as a GRS 1100-771 detected by Granat/WATCH as a fast (few hours long) X-ray transient (Castro-Tirado et al. 1999, A&A 347, 927), a similar episode might have been detected by space-borne high-energy detectors in the past days. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18242 SUBJECT: ANTARES neutrino detection: ANU 2.3m and Kepler K2 Observations of the Swift x-ray source DATE: 15/09/05 00:48:24 GMT FROM: Fang Yuan at ANU B. E. Tucker, K. Freeman, F. Yuan, C. Wolf, B. Schmidt, D. Bayliss, C. Onken (Australian National University) We report on the spectroscopic observation of the star associated with the Swift x-ray detection by Doric et al. (ATel #7987) which is within the ANTARES neutrino error region using the Wide Field Spectrograph (WiFeS - Dopita et al., 2007, ApSS, 310, 255) on the ANU 2.3m telescope at Siding Spring Observatory, NSW Australia, using the B7000/I7000 gratings (3500-9800 A, 1 A resolution). The spectrum shows features of a late-type (K5 - K7) dwarf star - strong MgH along with moderately-weak Balmer emission (i.e. H-beta and H-gamma). Additionally, the star was observed using the Kepler extended mission (K2) in Field 2 for about 70 days. A quick reduction of the K2 light-curve shows periodicity on the scale of about 1.5 days, indicating possible binarity. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18248 SUBJECT: Fermi GBM trigger 150907763 is not a GRB DATE: 15/09/07 21:11:44 GMT FROM: Peter Veres at UAH P. Veres reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 463342761/150907763 at 18:19:17.07 UT on the 7 September 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a particle event." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18257 SUBJECT: Fermi GBM trigger 463339482/150907725 is too weak to be classified DATE: 15/09/08 16:06:47 GMT FROM: Peter Veres at UAH P. Veres (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 463339482/150907725 at 17:24:38.64 UT on 7 September 2015 was tentatively classified as a GRB. After the re-analysis of the data we conclude that this trigger is too weak to be reliably classified." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18261 SUBJECT: Fermi GBM trigger 463422723/150908689 is not a GRB DATE: 15/09/08 18:32:26 GMT FROM: Peter Veres at UAH P. Veres reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 463422723/150908689 at 16:31:59.43 UT on 8 September 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a particle event." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18262 SUBJECT: Swift Trigger 654954 is not an astrophysical event DATE: 15/09/08 22:08:27 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 21:38:08 UT, the Swift Burst Alert Telescope (BAT) detected the commonly-seen source GRS 1915+105 (trigger=654954) but misidentified it as different, rarely-seen source due to a known race condition in the onboard software. This is not an astrophysical interesting event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18305 SUBJECT: Fermi GBM trigger 463890496/150914103 is not a GRB DATE: 15/09/14 03:30:22 GMT FROM: Matthew Stanbro at UAH/Fermi M. Stanbro reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 463890496/150914103 at 02:28:12.27 UT on 14 September 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is believed to be accidental due to South Atlantic Anomaly (SAA) entry." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18330 SUBJECT: GRB test of the new dual access DATE: 15/09/18 21:11:49 GMT FROM: Scott Barthelmy at NASA/GSFC This is a test of the new aragment that allows gcncirc and lvccirc to access the same sernum file. This is a test. Please ignore. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18351 SUBJECT: Fermi GBM trigger bn150920977 is not due to a GRB DATE: 15/09/21 02:38:37 GMT FROM: George A. Younes at George Washington U G. Younes reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 464484416/150920977 at 23:26:52.22 UT on 20 September 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18352 SUBJECT: ANTARES neutrino detection: Fermi GBM Observations DATE: 15/09/21 13:07:07 GMT FROM: Valerie Connaughton at UAH/NSSTC Lindy Blackburn (CfA), Michael S. Briggs (UAH), Eric Burns (UAH), Jordan Camp (NASA/GSFC), Nelson Christensen (Carleton College), Valerie Connaughton (USRA), Adam Goldstein (NASA/MSFC), Peter Jenke (UAH), Tyson Littenberg (UAH), Judith Racusin (NASA/GSFC), Peter Shawhan (UMD), Leo Singer (NASA/GSFC), John Veitch (Birmingham), Colleen Wilson-Hodge (NASA/MSFC), and Binbin Zhang (UAH) On September 1st, 2015, at 07:38:25 UT, the time of the reported neutrino detection by ANTARES (Dornic et al., GCN 18231), Fermi GBM was observing the reported neutrino position with several GBM detectors having a good geometry to the source. We searched for associated gamma-ray emission with 3 different search techniques. A seeded search for impulsive emission around the time and sky location of the detected neutrino yielded no candidates above the GBM background. The search method was developed to look for electromagnetic counterparts in the GBM data of sub-threshold gravitational wave signals found in the LIGO data (Blackburn et al. 2015, ApJS, 217, 8), and implemented here in a 60 s search window centered on the time and seeded with the position of the detected neutrino. A blind search for untriggered impulsive emission in the GBM data in the 11 hours centered on the neutrino detection yielded no candidates consistent with the position of the neutrino. This search technique was developed for the detection of untriggered short GRBs in the GBM data, and is also sensitive to long GRBs and other transients up to about 100 s in duration (Zhang et al., in preparation). Measurements using the Earth Occultation technique of the flux from the Swift XRT source reported within the ANTARES error box by Dornic et al. in the 24 period after the neutrino detection place a flux limit of 150 mCrab between 12 and 300 keV. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18389 SUBJECT: Swift Trigger 657564: a probable GRB DATE: 15/10/04 18:19:25 GMT FROM: Scott Barthelmy at NASA/GSFC S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 18:09:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151004A (trigger=657564). Swift did not slew due to the Earth-limb observing constraint. The BAT on-board calculated location is RA, Dec 213.585, -64.947, which is RA(J2000) = 14h 14m 20s Dec(J2000) = -64d 56' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, the real-time light curve does not show anything significant. Due to an observing constraint, Swift will not slew until T0+56.9 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18391 SUBJECT: Swift Trigger 657564: XRT prompt analysis DATE: 15/10/04 20:15:04 GMT FROM: Claudio Pagani at U of Leicester C. Pagani (U. Leicester), P. A. Evans (U. Leicester) and S. B. Cenko (GSFC) report on behalf of the Swift-XRT Team: The XRT began observing the field of the possible GRB 151004A (Swift trigger 657564, Cenko et al., GCN Circ. 18389) at 19:09:14.0 UT, 3609.3 seconds after the BAT trigger. No source was detected in 1.1 ks of promptly downlinked data, which covered 84% of the BAT error circle. We are waiting for the full dataset to detect and localise any possible XRT counterpart. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18392 SUBJECT: Swift Trigger 657564: MASTER-NET early optical observations. DATE: 15/10/05 09:23:49 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the probable GRB (Swift Trigger 657564) 24 sec after notice time and 108 sec after trigger time at 2015-10-04 18:10:55 UT. On our first (20s exposure) set we not found optical transient within SWIFT error-box (Cenko et. al GCN 18389) brighter then 16.0. Analysis of highly complicated proximity to the Milky Way (Galactic latitude l=-3.5) and strong winds (speed=65 km/h) The 5-sigma upper limit has been about 16.0 mag The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18412 SUBJECT: Swift Trigger 658045 is not a GRB DATE: 15/10/08 06:11:38 GMT FROM: David Palmer at LANL C. Gronwall (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:47:47 UT, the Swift Burst Alert Telescope (BAT) triggered on the combination of the rate increase due to the SAA and a marginal significance image fluctuation (trigger=658045). Swift slewed immediately to the image peak. The BAT light curve showed the usual rising background rate as expected on entry to the SAA. Because of the proximity to the SAA, the XRT centroided on a cosmic ray. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18414 SUBJECT: Fermi GBM trigger 466059859/151009211 is not a GRB DATE: 15/10/09 10:51:25 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (INFN Bari) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 466059859/151009211 at 05:04:15.57 UT on 9 October 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18417 SUBJECT: Fermi GBM trigger 466316973/151012187 is not a GRB DATE: 15/10/12 12:34:59 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (INFN Bari) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 466316973/151012187 at 04:29:29.04 UT on 12 October 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18419 SUBJECT: Fermi GBM trigger 466602792/151015495 is not a GRB DATE: 15/10/15 13:42:56 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 466602792/151015495 at 11:53:08.13 UT on 15 October 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18421 SUBJECT: Trigger 659734: Swift detection of SAX J1750.8-2900 or other source near Galactic center DATE: 15/10/16 01:48:57 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), K. L. Page (U Leicester) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 01:25:59 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst with a position consistent with SAX J1750.8-2900 (trigger=659734). Swift did not slew immediately to the location due to higher priority observations. The BAT on-board calculated location is RA, Dec 267.600, -29.018 which is RA(J2000) = 17h 50m 24s Dec(J2000) = -29d 01' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single soft FRED structure with a duration of about 8 sec. The peak count rate was ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger. Although this BAT detection was consistent in position with SAX J1750.8-2900 (within 71 arcseconds) the location near the Galactic center (lon,lat = 0.47,-0.94 degrees) has a high density of known and unknown sources, so the identification cannot be confirmed. Follow-up observations with the XRT are planned to determine the origin of the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18562 SUBJECT: Swift-BAT triggers are disabled DATE: 15/11/05 17:52:24 GMT FROM: Scott Barthelmy at NASA/GSFC S.Barthelmy (GSFC) on behalf of the Swift-BAT Team: Triggers have been disabled (as of 21:10 UT 31-Oct-15) in the Swift-BAT instrument while a thermal anomoly is being investigated. The XRT and UVOT instruments continue to operate normally, as are pre-planned and TOO observations. BAT is expected to return to normal opertaions in a few days. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18586 SUBJECT: Swift-BAT trigger 663164 is not a burst. DATE: 15/11/12 10:59:47 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), K. L. Page (U Leicester) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 10:28:11 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=663164) on what appears to be noise during the count rate rise associated with entry into the SAA. The image significance is low (6.5 sigma) and there is no significant peak in the light curve. Thus we believe that this trigger is not due to a GRB or other astrophysical event. The XRT began observing the field at 10:29:46.6 UT, 94.8 seconds after the BAT trigger. Initially XRT centroided on a cosmic ray. Further XRT data were not gathered until 1491 s after the trigger, due to SAA passage. No source was detected in 132 s of promptly-downlinked data. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18610 SUBJECT: Swift-BAT resumption of normal operations DATE: 15/11/16 17:40:42 GMT FROM: Scott Barthelmy at NASA/GSFC S.Barthelmy (GSFC) on behalf of the Swift-BAT Team: Swift-BAT experienced a transient problem with thermal control of the detector array commencing at 16:30 UT 31-Oct-15 ((GCN Circ 18562). Thermal control was re-established and full triggering to GRBs and transients resumed at 17:05 UT 06-Nov-15. Survey and Monitor data were somewhat degraded due to elevated temperature of the CZT and reduced bias voltage. Normal temperature and full bias voltage were achieved at 14:23 UT 13-Nov-15, resulting in a full recovery to nominal BAT performance. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18631 SUBJECT: Swift Trigger 664610: is unlikely a GRB DATE: 15/11/22 09:15:03 GMT FROM: Scott Barthelmy at NASA/GSFC K. L. Page (U Leicester), S. D. Barthelmy (GSFC) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift Team: At 08:49:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible source(trigger=664610). Swift slewed immediately to the target. The BAT on-board calculated location is RA, Dec 184.205, +17.599, which is RA(J2000) = 12h 16m 49s Dec(J2000) = +17d 35' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, there is nothing significant in the real-time TDRSS light curve. This is a 5.9 sigma trigger. The XRT began observing the field at 08:51:23.6 UT, 139.1 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 144 seconds with the White filter starting 143 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. We note that this is a low significance trigger (5.9 sigma); part of the sub-threshold program within BAT. Given that the initial XRT exposure did not produce a source (time-on-target was only 2.9 min), it is unlikely that this source is real, but we can not rule it out at this time. We will have to wait for more data in the next orbit. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18632 SUBJECT: Swift-BAT probable detection of an outburst from SGR J1819-1600 (AX J1818.8-1559) DATE: 15/11/22 12:50:16 GMT FROM: Scott Barthelmy at NASA/GSFC K. L. Page (U Leicester), S. Barthelmy (GSFC), and J. R. Cummings (NASA/UMBC) report on behalf of the Swift Team: At 12:09:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located a an SGR or a short GRB (trigger=664624). Swift did not slew due to Sun constraint. The BAT on-board calculated location is RA, Dec 274.742, -15.978, which is RA(J2000) = +18h 18m 58s Dec(J2000) = -15d 58' 40" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of less than 0.128 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 11:19 UT on 2016 February 10. There will thus be no XRT or UVOT data for this trigger before this time. We note that this is 1.7 arcmin from an INTEGRAL burst on 071017 which also was a short duration (~0.5 sec) (GCN Circ 6927) event. And therefore we strongly suspect that this new event is an SGR J1819-1600 (aka AX J1818.8-1559). Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18633 SUBJECT: Swift Trigger 664610 is not astrophysical DATE: 15/11/22 18:23:10 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy (GSFC), K. L. Page (U Leicester), and J. R. Cummings (NASA/UMBC) report on behalf of the Swift Team: Analyzing the full downlinked BAT data for Swift trigger 664610 (GCN Circ 18631) shows the image significance has dropped to 3.2 sigma, well below the 6.5 sigma requirement. In 4.9 ks of XRT data, starting 9.3 ks after the trigger, no X-ray sources are detected within the BAT error circle, to a 3-sigma upper limit of 2.3e-3 count s^-1. For a typical GRB spectrum, this corresponds to a 0.3-10 keV observed flux limit of 9e-14 erg cm^-2 s^-1. The combined data from BAT and XRT now show this trigger to be due to noise, and is not astrophysical. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18634 SUBJECT: Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600 DATE: 15/11/22 21:22:32 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-120 to T+242 sec from the recent telemetry downlinks, we report further analysis of an outburst from SGR J1819-1600 (trigger #664624) (Page, et al., GCN Circ. 18632). The BAT ground-calculated position is RA, Dec = 274.714, -15.981 deg, which is RA(J2000) = 18h 18m 51.4s Dec(J2000) = -15d 58' 52.6" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%. The mask-weighted light curve shows a single spike starting at T_zero. T90 (15-350 keV) is 0.032 +- 0.14 sec (estimated error including systematics). The time-averaged spectrum from T+0.000 to T+0.032 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.93 +- 0.38. The fluence in the 15-150 keV band is 1.5 +- 0.4 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.00 sec in the 15-150 keV band is 4.8 +- 1.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/664624/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18651 SUBJECT: Fermi GBM trigger 470375959/151128166 is not a GRB DATE: 15/11/28 06:34:49 GMT FROM: Elisabetta Bissaldi at U.Innsbruk/IAPP E. Bissaldi (INFN Bari) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 470375959/151128166 at 03:59:15.95 UT on 28 November 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18653 SUBJECT: Fermi GBM trigger 470290196/151127174 is not a GRB DATE: 15/11/28 17:30:12 GMT FROM: Hoi-Fung Yu at MPE Hoi-Fung Yu (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 470290196/151127174 at 04:09:52.29 UT on 27 November 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18654 SUBJECT: Fermi GBM trigger 470712580/151202062 is not a GRB DATE: 15/12/02 03:45:11 GMT FROM: Bagrat Mailyan at UAH Bagrat Mailyan (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 470712580/151202062 at 01:29:36.04 UT on 02 December 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18675 SUBJECT: Swift detection of 4U 1850-03 DATE: 15/12/09 06:34:43 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 06:08:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located 4U 1850-03 (trigger=666827). Swift did not slew due to observing constraint. The BAT on-board calculated location is RA, Dec 282.088, -2.421, which is RA(J2000) = 18h 48m 21s Dec(J2000) = -02d 25' 16" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, nothing is visible in the real-time TDRSS light curve. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 10:55 UT on 2016 February 15. There will thus be no XRT or UVOT data for this trigger before this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18710 SUBJECT: Fermi GBM trigger 472166503/151218890 is not a GRB DATE: 15/12/19 02:42:30 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 472166503/151218890 at 21:21:39.46 UT on 18 December 2015, tentatively classified as a GRB, is in fact not due to a GRB. This was an accidental trigger." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18712 SUBJECT: IBAS Alert 7313 is SGR J1935+2154 DATE: 15/12/21 10:50:37 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF-Milano) report: The position of the event reported in GCN 18711 is consistent with that of the known Soft Gamma-ray Repeater SGR J1935+2154 (GCN 16522). Due to an error in the software, this positional coincidence was not recognized and properly flagged in the alert packet n.7313 I apologize for the confusion. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18713 SUBJECT: Fermi GBM trigger 472271765/151220108 is not a GRB DATE: 15/12/21 12:48:56 GMT FROM: Hoi-Fung Yu at MPE Hoi-Fung Yu (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 472271765/151220108 at 02:36:01.57 UT on 20 December 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18714 SUBJECT: Fermi GBM trigger 151221690 is not a GRB DATE: 15/12/21 23:55:57 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 472408444/151221690 at 16:34:00.82 UT on the 21th of December 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a local particles." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18716 SUBJECT: Trigger 668097: Swift detection of V 404 Cyg DATE: 15/12/23 05:35:49 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 05:19:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located V 404 Cyg (trigger=668097). Swift did not slew due to a low merit value. The BAT on-board calculated location is RA, Dec 306.024, +33.874, which is RA(J2000) = 20h 24m 06s Dec(J2000) = +33d 52' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers, the real-time light curve does not show anything. This is a known source, and as such the assigned merit value was low enough to not allow an immediate slew. Swift will slew to this source at 06:37 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18717 SUBJECT: V404Cyg Swift Trigger 668097: DATE: 15/12/23 09:24:09 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, N.Tyurina, D. Vlasenko, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias O. Gress, K. Ivanov, N.M. Budnev, V.A. Poleshchuk, S.A. Yazev Irkutsk State University MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the V404 Swift Trigger 668097 13709 sec after notice time and 14050 sec after trigger time at 2015-12-23 09:14:02 UT. On our first (60s exposure) set we have found V404 in highe state within Swift error-box (ra=20 24 03 dec=+33 52 01 r=0.050000) ~ 17 mag . The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18718 SUBJECT: V404Cyg Swift Trigger 668097: MASTER-Tunka optical wake up detection DATE: 15/12/23 12:44:16 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs O. Gress, K. Ivanov, N.M. Budnev, V.A. Poleshchuk, S.A. Yazev Irkutsk State University E. Gorbovskoy, V. Lipunov, N.Tyurina, D. Vlasenko, V.Kornilov, P.Balanutsa,A.Kuznetsov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk We reported about V404 Cyg optical detection by MASTER-Amur (Yurkov et al., GCN 18717) after Swift BAT alert ( Barthelmy et al., 18716). MASTER-Tunka starts alert observations of V404 at 2015-12-23 10:16:20 UT (just after the sunset, 17447 sec after notice time and 17787 sec after trigger time). There is fast about half-magnitude variability at the interval about 10min time scale. Preliminary LC is available at http://master.sai.msu.ru/static/v404_23dec2015.png The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18719 SUBJECT: Fermi GBM trigger 151221730 is not a GRB DATE: 15/12/23 18:41:32 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 151221730/472411854 at 17:30:50.36 UT on the 21 of December 2015, tentatively classified as GRB, is in fact not due to GRB. This trigger is due to V404 Cyg.” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18721 SUBJECT: V404Cyg Swift Trigger 668097: TSHAO optical observations DATE: 15/12/24 18:31:34 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed V404 Cyg after Swift BAT trigger 668097 (Barthelmy et al., GCN 18716) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. Observations started on Dec., 23 (UT) 12:19:13. We obtained 165 images in R-filter of 30 s exposure. Preliminary light curve http://grb.rssi.ru/V404_Cyg/v404Cyg_20151223_lc.pngof the V404 Cyg can be found in http://grb.rssi.ru/V404_Cyg/v404Cyg_20151223_lc.png Photometry is based on following USNO-B1.0 stars ID R2 USNO-B1.0_id R2 1238-0435152 15.98 1239-0424177 14.99 1239-0424179 15.61 1238-0435111 16.33 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18722 SUBJECT: Fermi GBM trigger 472694170/151224997 is not a GRB DATE: 15/12/25 00:56:42 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 472694170/151224997 at 23:56:06.54 UT on 24 December 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to particle activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18767 SUBJECT: V404Cyg Swift Trigger 668097: AbAO optical observations DATE: 15/12/30 10:31:22 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), R. Inasaridze (AbAO), A. Volnova (IKI), V. Ayvazian (AbAO), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed V404 Cyg after Swift BAT trigger 668097 (Barthelmy et al., GCN 18716) with AS-32 (0.7m) telescope of Abastumani Observatory. Observations started on Dec., 28 (UT) 16:19:10. We obtained several unfiltered images of 60 s exposure. The source has a flare during our observations, the maximal brightness of the source during our observations is 15.5m at (UT) 16:22:39. It is also apparent that we observed only a small episode of new flaring activity of V404 Cyg. Preliminary light curve of the V404 Cyg can be found in http://grb.rssi.ru/V404_Cyg/v404Cyg_AAO_20151228_lc.png Photometry is based on following USNO-B1.0 stars USNO-B.1_id R2 1238-0434779 13.52 1238-0434864 14.12 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18769 SUBJECT: V404Cyg Swift Trigger 668097: CrAO RT-22 radio observations DATE: 15/12/30 11:12:31 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volvach (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed V404 Cyg after Swift BAT trigger 668097 (Barthelmy et al., GCN 18716) with RT-22 telescope at 36.8 GHz in several epochs. Following RATAN-600 radio detection (Trushkin et al., ATEL 8454) we detect the v404 Cyg source in a flaring mode. Preliminary fluxes are following Date UT, start Flux, Jy Err 2015-12-24 10:35 3.63 0.18 2015-12-25 10:55 2.87 0.14 2015-12-26 09:36 1.20 0.21 2015-12-27 09:38 1.46 0.22 2015-12-28 08:47 0.27 0.08 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18777 SUBJECT: Trigger 668877: Swift detection of V 404 Cyg DATE: 15/12/30 22:37:54 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), C. Gronwall (PSU), L. Izzo (URoma/ICRA), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 22:26:00 UT, the Swift Burst Alert Telescope (BAT) triggered and located V 404 Cyg (trigger=668877). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 305.945, +33.850, which is RA(J2000) = 20h 23m 47s Dec(J2000) = +33d 50' 59" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers, there is nothing obvious in the real-time light curve. The XRT began observing the field at 22:28:09.1 UT, 128.7 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 306.01806, 33.86606 which is equivalent to: RA(J2000) = 20h 24m 04.33s Dec(J2000) = +33d 51' 57.8" with an uncertainty of 3.8 arcseconds (radius, 90% containment). . This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.1 arcseconds from a known X-ray source: 1SXPS J202404.2+335155. This source is in the Swift XRT 1SXPS catalogue with a mean 0.3-10 keV count-rate of 0.0183 +/- 0.0015 ct/sec; see http://www.swift.ac.uk/1SXPS/1SXPSJ202404.2%2B335155 for details of these previous observations. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 132 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18778 SUBJECT: Trigger 668879: Swift detection of V 404 Cyg again DATE: 15/12/30 23:22:00 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), V. D'Elia (ASDC), L. Izzo (URoma/ICRA), A. Y. Lien (GSFC/UMBC) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 22:44:51 UT, the Swift Burst Alert Telescope (BAT) triggered and located V 404 Cyg (trigger=668879). Swift was already observing this source. The BAT on-board calculated location is RA, Dec 306.016, +33.850, which is RA(J2000) = 20h 24m 04s Dec(J2000) = +33d 51' 00" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows activity at ~T-50 sec and at T_zero, but there is gap in the data from T_zero to T+100 sec. The XRT began observing the field at 22:48:41.67 UT, 230.1 seconds after the BAT trigger. No source was detected in 175 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 250 seconds with the U filter starting 230 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. Results from the 2.7'x2.7' sub-image are not available at this time. The overlap of the 8'x8' region for the list of sources generated on-board and the XRT error circle is uncertain. No correction has been made for extinction. This is the second trigger from this source (GCN 18777). It triggered while Swift was observing as a result of the first trigger. As such XRT and UVOT have data before and during T_zero for this second trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18783 SUBJECT: MASTER-NET observations of V404Cyg Swift Trigger 668877 DATE: 15/12/31 10:33:12 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, N.Tyurina, D. Vlasenko, V.Kornilov, P.Balanutsa,A.Kuznetsov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute O. Gress, K. Ivanov, N.M. Budnev, V.A. Poleshchuk, S.A. Yazev Irkutsk State University Following Swift triggers 668877 and 668879 (Barthelmy et al. GCN 18777,18778) MASTER-Amur point to V404 Cyg directly after sunset ~10.3 h after the trigger time at 2015-12-31 08:49:10. We found V404 at a high state with unfiltered magnitude ~ 15.0 m. During the first hour of observing the object brightened up to 14.4. Dear colleagues MASTER team wishes you a Merry Christmas and a happy new year. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18785 SUBJECT: Trigger 668949: Swift detection of V 404 Cyg DATE: 15/12/31 17:31:09 GMT FROM: Kim Page at U.of Leicester S. D. Barthelmy (GSFC), V. D'Elia (ASDC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 17:17:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located V 404 Cyg (trigger=668949). Swift did not slew because of a higher merit value target already being observed. The BAT on-board calculated location is RA, Dec 305.996, +33.859, which is RA(J2000) = 20h 23m 59s Dec(J2000) = +33d 51' 34" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks with a total duration of about 40 sec. The peak count rate was ~1100 counts/sec (15-350 keV), at ~0 sec after the trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18916 SUBJECT: GRB 16017B: RATIR continued observations DATE: 16/01/21 17:11:22 GMT FROM: Antonino Cucchiara at NASA/GSFC Antonino Cucchiara(GSFC/STScI),Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC),William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We continued observing the field of GRB 160117B with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org ) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2016/01 21.17 to 2016/01 21.51 UTC (86.20 to 94.28 hours after the BAT trigger), obtaining a total of 6.26 hours exposure in the r and i bands. The optical afterglow is still detected and in comparison with the USNO-B1 catalog, we obtain the following detections: r 22.91 +/- 0.17 i 22.39 +/- 0.10 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18975 SUBJECT: Fermi GBM trigger 475675010/160128498 is not a GRB DATE: 16/02/02 15:54:30 GMT FROM: Hoi-Fung Yu at MPE H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 475675010/160128498 at 11:56:46.28 UT on 28 January 2016, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to solar activity." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19002 SUBJECT: Swift Trigger 672897 is probably not an astrophysical event DATE: 16/02/08 00:19:49 GMT FROM: David Palmer at LANL A. D'Ai (INAF-IASFPA), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 23:49:52 UT, the Swift Burst Alert Telescope (BAT) found a marginal significance fluctuation in an untriggered image (trigger=672897). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 156.059, +19.770 which is RA(J2000) = 10h 24m 14s Dec(J2000) = +19d 46' 14" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for an image trigger, there is no obvious variation in the immediately-available BAT lightcurve. The XRT began observing the field at 23:52:49.7 UT, 177.5 seconds after the BAT trigger. No source was detected in 235 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 250 seconds with the U filter starting 339 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. As part of a search for nearby sources, Swift slews to confirm or refute marginal significance events that are near the line-of-sight to nearby galaxies. Based on the lack of a BAT rate trigger, the low significance of the original detection (5.9 sigma) the lack of an XRT detection, and the distance to the suggested host galaxy (12 arcmin) we believe that this event is merely a noise fluctuation in the BAT imager and not an astrophysical event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19012 SUBJECT: Fermi GBM trigger 477254668/160215781 is not a GRB DATE: 16/02/15 20:06:20 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 477254668/160215781 at 18:44:24.52 UT on 15 February 2016, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to solar activity." -- Matthew C. Stanbro Fermi GBM Graduate Research Assistant University of Alabama in Huntsville //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19013 SUBJECT: MAXI/GSC search for an X-ray counterpart of GW150914 DATE: 16/02/16 12:31:05 GMT FROM: Nobuyuki Kawai at Tokyo Tech M. Serino (RIKEN), H. Negoro (Nihon U.), N. Kawai (Tokyo Tech) S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), M. Arimoto, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), A. Yoshida, T. Sakamoto, H. Ohtsuki Y. Kawakubo (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.), Y. Tsuboi, S. Kanetou, Y. Nakamura, R. Sasaki (Chuo U.), M. Yamauchi, D. Itoh, (Miyazaki U.) K. Yamaoka (Nagoya U.), M. Morii (ISM) report on behalf of the MAXI team: We reexamined the MAXI/GSC all-sky X-ray images (2-20 keV) obtained in the orbits preceding and following the gravitational wave event LIGO/Virgo G184098 at 2015-09-14T09:50:45 UTC (GW150914; Abbott et al. 2016). In each of the 92-min orbits, MAXI/GSC scanned more than 90% of the localization (90% confidence) regions in the bayestar skymap. No significant new source was found in these scans. The elapsed time of each scan since the trigger time is: -5147 ~ -4614 s (preceding the event) +409 ~ +937 s (scan in the orbit immediately after the event) +5964 ~ +6492 s (second orbit after the event) +11530 ~ +12050 s (third orbit after the event) +17082 ~ +17593 s (fourth orbit after the event) The 3-sigma upper limit of each scan for the X-ray flux is about 1x10^-9 erg/s/cm^2 in 2-20 keV. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19031 SUBJECT: Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253 DATE: 16/02/20 14:03:26 GMT FROM: Kim Page at U.of Leicester A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 13:34:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible source near IGR17488-3253 (trigger=674752). Swift will not slew to the source as the ongoing observations of GRB 160220B have a higher priority. The BAT on-board calculated location is RA, Dec 267.196, -32.939 which is RA(J2000) = 17h 48m 47s Dec(J2000) = -32d 56' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, there is nothing significant in the real-time TDRSS light curve. We note that this is a low significance trigger (5.9 sigma), part of the sub-threshold program within BAT. Given that we lack XRT data, we cannot at present confirm that the source is real. We will have to wait until the full BAT dataset is transferred to ground to establish the reality of this trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19044 SUBJECT: Swift trigger 674752 is likely due to a noise fluctuation DATE: 16/02/21 21:01:58 GMT FROM: Amy Lien at GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), D. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf of the Swift Team: We conclude that Swift trigger 674752 (Lien et al., GCN Circ. 19031) was likely the result of noise fluctuations. We have analyzed the BAT data set from T-239 to T+963 sec from the recent telemetry downlink. We find that there is no sign of significant emission from the trigger location at any point in this interval. But with a significance of 5.2 sigma, we can not rule out an astrophysical source. No XRT or UVOT data are available for this trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19053 SUBJECT: Correction to the title of Swift GCN 19051 DATE: 16/02/22 14:05:01 GMT FROM: Massimiliano de Pasquale at IASF-Palermo M. De Pasquale report on behalf of the Swift/UVOT team: The title of the previous GCN Circ. 19051 should be "Further Swift/UVOT observations of GRB 160220B". We apologize for the mistake.