//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12122 SUBJECT: GRB 110709B: Swift detection of a burst DATE: 11/07/09 21:46:06 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU), R. L. C. Starling (U Leicester) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 21:32:39 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110709B (trigger=456967). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 164.614, -23.484 which is RA(J2000) = 10h 58m 27s Dec(J2000) = -23d 29' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows overlapping peaks with a total duration of about 60 sec. The peak count rate was ~4200 counts/sec (15-350 keV), at ~30 sec after the trigger. The XRT began observing the field at 21:34:00.4 UT, 80.5 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 164.6552, -23.4550 which is equivalent to: RA(J2000) = 10h 58m 37.24s Dec(J2000) = -23d 27' 17.9" with an uncertainty of 5.3 arcseconds (radius, 90% containment). This location is 171 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 150 seconds with the White filter starting 91 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 expected extinction corresponding to E(B-V) of 0.05. 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: 12124 SUBJECT: GRB 110709B: Swift detection of renewed activity at T+11 minutes. DATE: 11/07/09 22:17:07 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), 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), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU), R. L. C. Starling (U Leicester) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 21:43:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located a second event (trigger=456969) from the same location as trigger 456967. Swift did not slew to this location. However, it was already on the boresight of all 3 instruments from the previous trigger. The BAT on-board calculated location is RA, Dec 164.647, -23.464, which is RA(J2000) = 10h 58m 35s Dec(J2000) = -23d 27' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a broad hump begining around T-100, followed by an episode of several overlapping peaks structure with a duration of about 40 s, and another peak at T+200s, for a total duration of this outburst of at least 300 s. The peak count rate was ~5000 counts/sec (15-350 keV), at ~1 sec after the trigger. This is a second outburst from the same location as GRB 110709B at T+11 minutes, with comparable intensity and light curve characteristics to the initial outburst. The light curve is sharp with rapid variations on the 1-second timescale, which is uncharacteristic of late time flares in GRB afterglows. There is no obvious bright activity seen in the BAT lightcurve between the two outbursts. The location is well away from the Galactic plane, and its spectrum is much harder than typical Galactic transients. This is a highly unusual event, and follow-up observations should be a high priority. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12126 SUBJECT: GRB 110709B: possible quiescent source in DSS DATE: 11/07/09 23:41:46 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (University of Warwick) reports: "Inspection of DSS-II images of the region around GRB 110709B (Cummings et al. GCN 12122) shows a faint optical source at a location of RA(J2000) 10:58:37.34 DEC(J2000) -23:27:21.6 offset 3.9" from the centre of the XRT error circle (which currently has a 5.3", 90% confidence error). The source is apparently also detected in USNO-A2.0, with reported magnitudes of B=21.2, R=17.9 (although at this faint level the associated errors are large). This source may be a quiescent counterpart of GRB 110709B, although could also be an unrelated background (or foreground) source. The probability of chance alignment with a source with R~18 in this error region is ~1-2% (e.g. Bloom, Kulkarni, Djorgovski 2002, AJ 123, 1111)" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12128 SUBJECT: GRB 110709B: Gemini-South optical observations DATE: 11/07/10 01:27:35 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) reports on behalf of a larger collaboration: "We observed the field of the unusual GRB 110709B (GCNs 12122, 12124) with GMOS on the Gemini-South 8-m telescope starting on 2011 July 10.032 UT (3.2 hr after the initial trigger). Images were obtained at high airmass and in poor seeing (1.7"). In a stack of 5x180 sec r-band exposures we find a single faint source within the XRT error circle (GCN 12122) at (J2000): RA = 10:58:37.38 DEC = -23:27:21.21 With an uncertainty of about 0.3" in each coordinate. This source is consistent with the position of the DSS-II source reported by Levan (GCN 12126). Additional analysis is in progress." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12129 SUBJECT: GRB 110709B: GROND Detection of an Afterglow Candidate DATE: 11/07/10 01:36:14 GMT FROM: Adria C. Updike at Clemson U Adria C. Updike (NASA/GSFC), Felipe Olivares E., Jochen Greiner (both MPE Garching), and D. Alexander Kann (Tautenburg Obs.) report on behalf of the GROND team: We observed the field of the extremely long GRB 110709B (Swift trigger 456967; Cummings et al., GCN #12122, Barthelmy et al., GCN #12124) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observations started at 22:34 UT on the 9th of July 2011, 62 minutes after the GRB trigger, and are continuing. They were performed at an average seeing of 1.5" and at an average airmass of 1.3. We found two point sources within the 5".3 Swift/XRT error circle reported by Cummings et al. (GCN #12122). The first one is consistent with the source in the DSS which was reported by Levan (GCN # 12126) and confirmed by Berger (GCN #12128) and we furthermore detect a second, fainter source at RA (J2000.0) = 10h 58m 37.03s DEC (J2000.0) = -23d 27' 20.8" with an uncertainty of 0.5" in each coordinate. Based on 460 s of total exposures with mid-time 94 min after the trigger, we estimate preliminary r'-band magnitudes of 20.9 +/- 0.1 for the DSS source and 22.15 +/- 0.15 for the second source, both calibrated against GROND zero points (in AB system). The given magnitudes are not corrected for the Galactic foreground extinction corresponding to a reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998). At the moment, we cannot confirm if this second source is fading, but we suggest it as an afterglow candidate for GRB 110709B. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12130 SUBJECT: GRB 110709B: Preliminary Swift-BAT refined analysis DATE: 11/07/10 01:47:27 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): We report further analysis of BAT GRB 110709B (triggers #456967 and #456969; Cummings, et al., GCN Circ. 12122 and Barthelmy, et al., GCN Circ. 12124). Because of the interesting nature of this event, we are posting preliminary versions of the "refined" processing on the two triggers of GRB 110709B. The automated analysis of each trigger is provided separately. We will likely post the final refined analysis later when all of the full data is downlinked, and the combined analysis can be performed. At present, the first of the two BAT triggers (trigger #456967) consists of data from T-61 to T+234 sec. The second trigger (trigger #456969) consists of only a small amount of data from T-11 to T+63 sec. The two triggers are 645 sec apart. The BAT ground-calculated position of the first trigger (#456967) is, RA, Dec = 164.668, -23.470 deg, which is RA(J2000) = 10h 58m 40.3s Dec(J2000) = -23d 28' 11.4" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 57%. The position derived from the second trigger (#456969) is RA, Dec = 164.664, -23.500 deg, which is RA(J2000) = 10h 58m 39.4s Dec(J2000) = -23d 29' 59.6" with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100% (on the BAT bore sight as a result of the slew from the first trigger). The two positions are separated by 1.8 arcmin. The mask-weighted light curve of the first trigger, trigger #456967, shows the first peak of the cluster of peaks starting at ~T-30 sec (note that the partial downlinked data start only at T-61 sec), peaks at ~T+15 sec, and ends at T+130 or T+170 sec. T90 (15-350 keV) is 55.6 +- 3.2 sec (estimated error including systematics). The time-averaged spectrum of the data for the first trigger, trigger #456967, from T-27.4 to T+46.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.29 +- 0.04. The fluence in the 15-150 keV band is 9.4 +- 0.2 x 10-6 erg/cm2. The 1-sec peak photon flux measured from T+13.59 sec in the 15-150 keV band is 3.4 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The mask-weighted light curve of the second trigger, #456969, shows emission starting some time before the current data set starting at T=21:43:25.4 - 11 sec and extending beyond the T=21:43:25.4 + 63 sec of the partially downlinked data. The time-averaged spectrum of the second trigger, #456969, from T-8.2 to T+52.8 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.08 +- 0.17, and Epeak of 171.5 +- 81.8 keV (chi squared 36.6 for 56 d.o.f.). A fit to a simple power law gives a photon index of 1.39 +- 0.04 (chi squared 47.2 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at Trigger 456967: http://gcn.gsfc.nasa.gov/notices_s/456967/BA/ Trigger 456969: http://gcn.gsfc.nasa.gov/notices_s/456969/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12131 SUBJECT: GRB 110709B : A possible source in USNO B 1.0 DATE: 11/07/10 01:49:29 GMT FROM: L.P. Xin at NAOC L. P. Xin and J.Y Wei reports: We noted that A. J. Levan reports (GCN 12126) that a source was detected in USNO-A2.0, with a magnitude of B=21.2, R=17.9. Its coordinates are: RA(J2000): 10:58:37.34 DEC(J2000): -23:27:21.6 Epoch:(J2000) We check the USNO-B1.0 catalog and find that this source above reported by Levan (GCN 12126) disappeared in USNO-B1.0 catalog. However, another source was detected in USNO-B1.0 at the errorbox of X-ray counterparts. Its coordinates are RA(J2000) 10:58:37.00 DEC(J2000) -23:27:19.94 Epoch:(J2000) Its magnitudes are reported as R=19.69, B=21.08. The coordinates are consistent with the report of Updike et al. (GCN 12129). Further observations are encouraged, especially the redshift measurement, to check out weather this source is the counterpart of GRB 110709B or just a foreground or background source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12132 SUBJECT: GRB 110709B: Gemini-South additional analysis and photometry DATE: 11/07/10 02:10:22 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) reports on behalf of a larger collaboration: "Additional inspection and photometry of our Gemini-South r-band image (GCN 12128) reveals a second, fainter source (S2) at the following coordinates (J2000): RA = 10:58:36.955 DEC = -23:27:20.62 with an uncertainty of about 0.8" (due to centroid uncertainty). This position is consistent with the faint source detected by GROND (GCN 12129). Photometry of the two sources using the Gemini-South/GMOS standard photometric zero-point yields the following magnitudes: S1: r = 21.28+/-0.05 mag ("DSS" source) S2: r = 22.18+/-0.12 mag Taken at face value, the brightness of S2 is consistent with the GROND value (r=22.15+/-0.15 mag; GCN 12129), suggesting that S1 has actually faded by about 0.3+/-0.15 mag between 1 and 3.2 hours after the initial trigger. Alternatively, if the offset relative to the GROND photometry of S1 (r=20.9+/-0.1 mag) is due to a zero-point offset, the resulting brightness of S2 is r = 21.9+/-0.1 mag. This is marginally consistent with the GROND value (r=22.15+/-0.15 mag) which was obtained about 2.2 hours earlier than our observations. To determine which scenario is correct relative to the GROND photometry, we measure the brightness of the star at: RA = 10:58:38.053 DEC = -23:26:31.78 to be r = 18.25 mag." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12135 SUBJECT: Konus-Wind observation of GRB 110709B DATE: 11/07/10 10:56:50 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 long GRB 110709B (Swift-BAT trigger #456967: Cummings et al., GCN 12122; Barthelmy et al., GCN 12130) triggered Konus-Wind at T0=77564.576s UT (21:32:44.576) The burst light curve shows a multi-peaked pulse with a total duration of ~70 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110709_T77564/ As observed by Konus-Wind the burst had a fluence of (2.6 ± 0.2)x10-5 erg/cm2, and a 256-ms peak flux, measured from T0+13.824 s, of (1.1 ± 0.1)x10-5 erg/cm2/s (both in the 20 keV - 5 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+41.216 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which alpha = -1.0 (-0.13, +0.14), and Ep = 278(-32, +43) keV, chi2 = 62.7/73 dof. The spectrum at the maximum count rate (measured from T0+8.448 to T0+16.640 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which alpha = -0.56 (-0.26, +0.30), and Ep = 231(-28, +38) keV, chi2 = 65.9/73 dof. The renewed source activity (Swift-BAT trigger #456969: Barthelmy et al., GCN 12124) fell into the telemetry gap but was recorded by the instrument's spare count rate measurement channel. This low-resolution record (in the 70-300 keV energy range) shows a double-pulsed structure lasting for ~100 s from T0+573 s to T0+675 s (21:42:17 - 21:43:59) and having slightly weaker intensity as compared to the initial burst. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12136 SUBJECT: GRB 110709B: Enhanced Swift-XRT position DATE: 11/07/10 11:33:08 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 9216 s of XRT Photon Counting mode data and 18 UVOT images for GRB 110709B, 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 = 164.65448, -23.45489 which is equivalent to: RA (J2000): 10h 58m 37.08s Dec (J2000): -23d 27' 17.6" with an uncertainty of 1.4 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. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12137 SUBJECT: GRB 110709B: correction to GCN 12135 (Konus-Wind peak flux) DATE: 11/07/10 13:10:28 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks on behalf of the Konus-Wind team: The correct value of GRB 110709B peak energy flux measured by Konus-Wind is (1.1 ± 0.1)x10-6 erg/cm2/s, this is an order of magnitude lower than it is reported in GCN 12135. We apologize for this misprint. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12140 SUBJECT: GRB 110709B: Swift/UVOT Detection of Possible Optical Flaring DATE: 11/07/10 14:35:59 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110709B 91 s after the initial BAT trigger (Cummings et al., GCNC 12122). We detect a source at the location of the GROND source reported by Updike et al. (GCNC 12129). The preliminary UVOT position is: RA (J2000) 10:58:37.03 = 164.65429 (deg) Dec (J2000) -23:27:20.9 = -23.45581 (deg) with an estimated uncertainty of 0.49 arcsec (radius, 90% confidence, statistical + systematic). Preliminary photometry indicates that this source may have flared at approximately the time of the second BAT trigger (Barthelmy et al., GCNC 12124). Preliminary magnitudes and 3-sigma upper limits, using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the white exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag Err white (fc) 91 241 147 >21.1 3-sigma upper limit white 583 603 19 20.10 0.49 white 756 776 19 19.74 0.37 white 858 1008 147 20.94 0.34 white (fc) 6245 6444 197 21.19 0.38 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 mag in the direction of the burst (Schlegel et al. 1998). Further analysis of the Swift/UVOT data is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12142 SUBJECT: GRB 110709B: Swift-XRT refined Analysis DATE: 11/07/10 22:13:25 GMT FROM: Valerio D'Elia at ASDC V. D'Elia, G. Stratta and J. R. Cummings (NASA/UMBC) report on behalf of the Swift-XRT team: We have analysed 16 ks of XRT data for GRB 110709B (Cummings et al. GCN Circ. 12122), from 70 s to 36.8 ks after the BAT trigger. The data comprise 2.3 ks in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 12136). The light curve shows a prolonged and powerful flaring activity up to T0+2 ks. The late-time light curve (from T0+5.4 ks) can be modelled with a power-law decay with a decay index of alpha=1.08 (+/-0.04). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.550 (+/-0.020). The best-fitting absorption column is 1.79 (+/-0.07) x 10^21 cm^-2, in excess of the Galactic value of 5.6 x 10^20 cm^-2 (Kalberla et al. 2005). We stress that this fit averages over strong spectral variations. In fact, the hard-to-soft band ratio during this time period varies from about 0.5 to about 3. The PC mode spectrum has a photon index of 2.19 (+/-0.08) and a best-fitting absorption column of 2.14 (+0.22, -0.21) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (6.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.14 (+0.22, -0.21) x 10^21 cm^-2 Galactic foreground: 5.6 x 10^20 cm^-2 Excess significance: 16.8 sigma Photon index: 2.19 (+/-0.08) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00456967. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12143 SUBJECT: GRB 110709B: burst detection from Swift-BAT slew data DATE: 11/07/10 22:39:52 GMT FROM: Antonio Copete at Harvard U A. Copete, J. Grindlay (Harvard) S. Barthelmy, C. Markwardt, N. Gehrels (NASA/GSFC) We report the detection of the early emission from GRB 110709B (GCNs 12122, 12124) by the BAT Slew Survey (BATSS) in the slew that started at 21:32:53 UT and lasted 55 sec, immediately following the original on-board detection. The ground-calculated position is RA, Dec = 164.654, -23.464 deg, which is RA (J2000) = 10h 58m 37.0s Dec (J2000) = -23d 27' 51" with an uncertainty of 1.8 arcmin (90% confidence radius, incl. systematics). The trigger was issued as a result of simultaneous independent detections of 44.0 and 31.3 sigma from imaging in the 15-50 keV and 50-150 keV energy bands, respectively. The burst mask-tagged lightcurve in the 15-150 keV band shows a fading profile with several overlapping peaks within it, from the start of the the slew at T+14s until fading into the background at T+48s during the course of the slew. The time-averaged spectrum over the 34 sec duration of the burst within the slew is best fit by a power law with an exponential cutoff, with photon index 1.06 +- 0.18, and Epeak of 175.7 (+151.3/-44.5) keV. The fluence in the 15-150 keV band is 4.9 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux (from T+17.0s, 15-150 keV) is 3.35 +- 0.25 photons/cm2/sec. All errors are quoted at 90% confidence level. The analysis software for the BAT Slew Survey has undergone a thorough revision, and its burst-finding function to process downlinked slew data and issue automated real-time alerts is now fully operational. At the current rate of ~80 ksec of instrument exposure time downlinked per month (about 30% of all slew data), it is expected to to detect ~0.5 new bursts per month, separate from those already detected in pointing mode. BATSS alert notices are distributed through the GCN: http://gcn.gsfc.nasa.gov/gcn/swift.html#tc2x2//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12144 SUBJECT: GRB 110709B BAT refined analysis DATE: 11/07/10 23:00:09 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), C. B. Markwardt (GSFC), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU/NASA/GSFC), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+1608 sec, we report further analysis of BAT GRB 110709B (triggers #456967 and #456969) (Cummings, et al., GCN Circ. 12122, Barthelmy, et al., GCN Circ. 12124, and Barthelmy, et al., GCN Circ. 12130), where T is the time of the first trigger. The BAT ground-calculated position for the second event (trigger #456969) is RA, Dec = 164.655, -23.456 deg which is RA(J2000) = 10h 58m 37.3s Dec(J2000) = -23d 27' 20.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. This position is 1.0 arcmin from the ground- calculated position of the first event (trigger #456967), which had an estimated uncertainty of 1.1 arcmin. The position of 456969 is 0.07 arcmin from the enhanced XRT position (Beardmore et al., GCN Circ 12136). The two events are clearly from the same object. The main emission in the first event lasted from about T-28 sec to T+55 sec with a faint declining emission detectable to about T+180 sec. T90 (15-350 keV) of the first event was 55.6 +- 3.2 sec. There was no flux detectable in BAT from about T+180 to about T+485 sec. The second event lasted from T+485 sec to T+865 sec with a variety of peaks and spikes on top of an ongoing emission. T90 (15-350 keV) of the second event was 259.2 +- 8.8 sec (estimated error including systematics). Considering the two events as a whole, T90 was about 846 +- 6 seconds. The lightcurve of the second event was clearly different from the first, so the unusual separation of two episodes of bright emission was not the result of gravitational lensing. The separation of episodes is unusual but not unprecedented. For instance, GRBs 041219A, 060124, 070721B, and 050820A also had multiple episodes separated by long intervals with no detectable emission. The source came into the BAT FOV at ~T-75 (during a slew that started at T-200sec and settled at ~T-20 sec.). The source was above the Earth horizon for about 20 minutes prior to trigger 456967. We cannot rule out faint or soft emission prior to about T-75 sec, but for 20 minutes prior to the first trigger, there was no strong emission above about 50 keV. The time-averaged spectrum of the data for the first trigger, trigger #456967, from T-27.4 to T+46.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.29 +- 0.04. The fluence in the 15-150 keV band is 9.4 +- 0.2 x 10-6 erg/cm2. The 1-sec peak photon flux measured from T+13.59 sec in the 15-150 keV band is 3.4 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The time-averaged spectrum from T+518.5 to T+855.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.44 +- 0.04. The fluence in the 15-150 keV band is 1.44 +- 0.04 x 10^-05 erg/cm2. The 1-sec peak photon flux measured from T+1.06 sec in the 15-150 keV band is 3.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. Examination of archival pre-trigger data from when the location of GRB 110709B was in the BAT field of view reveals no significant precursor emission. In the two observations closest in time to the trigger, upper limits are set at 0.005 ct/s/cm2 (T-6903 to T-6345 sec) and 0.004 ct/s/cm2 (T-12526 to T-11986 sec) and T-6903 to T-6345 sec). There is also no emission detected in daily averages going back to 2011 June 1, with an average upper limit of 0.002 ct/s/cm2 (~8 mCrab). All errors are 1-sigma for the 15-50 keV energy band. In the 70-month averaged BAT Hard X-ray Survey, the three-sigma upper limit at the position of the XRT counterpart for GRB 110709B is 6.4e-12 ergs/cm2/sec in the 14-195 keV band. The results of the batgrbproduct analysis are available at Trigger 456967: http://gcn.gsfc.nasa.gov/notices_s/456967/BA/ Trigger 456969: http://gcn.gsfc.nasa.gov/notices_s/456969/BA/ http://gcn.gsfc.nasa.gov/notices_s/comb_456967_456969/BA/top.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12151 SUBJECT: GRB 110709B: Submm observations from APEX DATE: 11/07/12 04:59:13 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (DARK/NBI), A. Lundgren, C. De Breuck, G. Siringo, R. Parra and C. Agurto (ESO) report on behalf of a larger collaboration: We have observed the field of GRB 110709B (Cummings et al. GCN 12122) using LABOCA/APEX at Chajnantor (Chile) in the 870 micrometer band. Observations began on July 11 2011 at 21:31 UT (2.00 days after the burst), with an on source time of 106 min and PWV of 0.8mm. We used the photometric mode, centred at the refined XRT position (Beardmore et al. GCN 12136). Initial data reduction, using CRUSH and BoA does no not detect any significant emission, obtaining a formal flux on the source position of 1.4+/-2.3mJy (3-sigma limit of 6.9mJy). We acknowledge the effort done by the APEX staff to get the telescope back into operations after a 3m snow fall at Chajnantor. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12155 SUBJECT: GRB 110709B: Additional Gemini observations and deep limits on an optical afterglow DATE: 11/07/14 01:20:27 GMT FROM: Wen-fai Fong at CFA W. Fong and E. Berger (Harvard) report: "We re-observed the location of GRB 110709B (GCNs 12122, 12124) with GMOS on the Gemini-South 8-m telescope starting on 2011 July 13.958 UT (4.1 days after the initial trigger). Images were obtained in mediocre seeing (1.35"). In a stack of 5x180 sec r-band exposures we still detect sources S1 and S2 (GCNs 12126, 12128, 12129, 12132). Neither source exhibits evidence for fading in photometry relative to several nearby stars, and in digital image subtraction using the ISIS package. We further note that both S1 and S2 are located outside of the refined XRT error circle (GCN 12136). We do not detect any other sources within the refined XRT circle in either of our Gemini epochs to a limit of >23.8 mag at delta-t=3.2 hours and >25.1 mag at 4.1 days. A comparison to the X-ray flux density at 3.2 hours (F_nu,X ~ 12 microJy**) requires a spectral index of beta_OX > 0.4 for F_nu ~ nu^beta. This is a highly unusual spectral index since typical values are beta_OX ~ -0.6 to -1, and events with beta_OX > -0.5 are considered "dark bursts". Such an unusual spectral index may be indicative of a high redshift origin (z>4.5 based on r-band non-detection) or a non-GRB origin similar to the recent GRB 110328A." ** http://www.swift.ac.uk/xrt_curves/00456967/ [GCN OPS NOTE(14jul11): Per author's request, the missing footnote was added.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12157 SUBJECT: GRB 110709B: Swift/UVOT Observations DATE: 11/07/15 12:00:00 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) and J. R. Cummings (CRESST/UMBC/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 110709B starting 70 s after the BAT trigger (Cummings et al., 2011, GCNC 12122). Settled observations started at 91 s. We do not detect a source at the UVOT-enhanced XRT position (Beardmore, et al., 2011, GCNC 12136) in any of the UVOT filters. Preliminary 3-sigma upper limits for detecting a source in the finding charts and in the co-added images, are Filter TSTART TSTOP EXPOSURE Mag --------------------------------------------------- white (FC) & 91 & 241 & 147 & >21.1 u (FC) & 303 & 553 & 246 & >20.5 white (FC) & 858 & 1008 & 147 & >21.3 --------------------------------------------------- v & 633 & 64,817 & 3519 & >21.5 b & 558 & 54,124 & 3664 & >22.4 u & 303 & 59,906 & 4680 & >22.2 uvw1 & 682 & 59,264 & 4730 & >22.2 uvm2 & 1235 & 58,357 & 3732 & >22.3 uvw2 & 782 & 64,122 & 3530 & >22.4 white & 91 & 30,997 & 3107 & >23.0 --------------------------------------------------- We find weak evidence for variability at the location of the USNO-B1.0 source 3.5 arcsec WNW of the XRT position at the time of the second BAT trigger (Barthelmy et al. 2011, GCNC 12124). Preliminary photometry is Filter TSTART TSTOP EXPOSURE Mag Err Sigma ---------------------------------------------------------------- white & 91 & 241 & 147 & >21.1 3-sigma UL white & 583 & 776 & 39 & 20.08 0.35 3.3 white & 858 & 1008 & 147 & >21.3 3-sigma UL white & 1161 & 2047 & 117 & 20.96 0.36 3.1 white & 6245 & 6444 & 197 & >21.4 3-sigma UL white & 7679 & 11,397 & 340 & 21.07 0.37 3.1 white & 11401 & 12,005 & 590 & >21.9 3-sigma UL white & 17893 & 18,800 & 885 & 20.98 0.16 7.8 white & 30335 & 30,997 & 644 & 21.39 0.23 5.2 ---------------------------------------------------------------- We note that both the USNO-B1.0 source and the XRT position are located in the coincidence loss halo of a bright star, which makes precision photometry difficult. It is not clear if the apparent variability seen at the location of the USNO-B1.0 source is real or not. The quoted magnitudes and upper limits have not been corrected for the large, but uncertain, Galactic extinction along the line of sight to this burst (E_{B-V} = 0.05 mag, Schlegel et al. 1998, ApJS, 500, 525). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12172 SUBJECT: GRB 110709B : Suzaku WAM observation of the prompt emission DATE: 11/07/19 01:12:55 GMT FROM: Norisuke Ohmori at Miyazaki U N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki), M. Ohno, Y. Hanabata, T. Uehara, T. Takahashi, M. Mizuno, Y. Fukazawa (Hiroshima U.), K. Yamaoka (Aoyama Gakuin U.), S. Sugita (Nagoya U.), T. Yasuda, Y. Terada, M. Tashiro, W. Iwakiri, K. Takahara (Saitama U.), M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), Y. Urata, P. Tsai, C-J. Chuang (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report: The long GRB110709B (Swift/BAT trigger #456967, GCN 12122 ; Cummings et al.,) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 21:32:44.453 UT (=T0). The observed light curve shows multiple peaks starting at T0-10 s, ending at T0+40 s, with a duration (T90) of about 48 seconds. The fluence in 100 - 1000 keV was 1.53 (-0.16, +0.29) x 10^-5 erg/cm^2. The 1-s peak flux measured from T0+25.5 s was 1.70 (-0.43, +0.30) photons/cm^2/s in the same range. Preliminary result shows that the time-averaged spectrum from T0-12 s to T0+40 s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 0.61 (-1.16, +0.95), and Epeak 286 (-80, +41) keV (chi^2/d.o.f. = 12.6/14). The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12190 SUBJECT: GRB 110709B / EVLA detection of radio counterpart DATE: 11/07/21 22:04:14 GMT FROM: Ashley Zauderer at CfA A. Zauderer and E. Berger (Harvard/CfA) report on behalf of a larger collaboration: "We observed GRB 110709B (GCN 12122) with the EVLA on several occasions between 2011 July 11 and 16 UT at a frequency of 5.8 GHz. Within the XRT error circle (GCN 12136) we find a single unresolved radio source which brightened by about a factor of 1.6 between 2.1 and 7.0 days after the burst. The source is located at (J2000): RA = 10:58:37.114 Dec = -23:27:16.760 The coincidence with the XRT position and the rising flux indicate that this source is the radio afterglow of GRB 110709B. No optical counterpart is detected at this position in our Gemini r-band observations (GCNs 12132, 12155) to a limit of >23.8 mag at 3.2 hours and >25.1 mag at 4.1 days. Along with the bright X-ray counterpart, the radio source provides additional support that GRB 110709B is a dark burst. We thank the EVLA staff for their support of these observations."