//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12158 SUBJECT: GRB 110715A: Swift detection of a bright burst with an optical counterpart DATE: 11/07/15 13:26:17 GMT FROM: Scott Barthelmy at NASA/GSFC E. Sonbas (GSFC/USRA/Adiyaman Univ.), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), V. D'Elia (ASDC), M. De Pasquale (UCL-MSSL), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), O. M. Littlejohns (U Leicester), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), S. R. Oates (UCL-MSSL), C. Pagani (U Leicester), K. L. Page (U Leicester), P. Romano (INAF-IASFPA), A. Rowlinson (U Leicester), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), G. Stratta (ASDC), C. A. Swenson (PSU) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team: At 13:13:50 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110715A (trigger=457330). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 237.660, -46.233 which is RA(J2000) = 15h 50m 38s Dec(J2000) = -46d 13' 59" 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 15 sec. The peak count rate was ~70,000 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 13:15:21.9 UT, 90.9 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 237.6832, -46.2326 which is equivalent to: RA(J2000) = 15h 50m 43.96s Dec(J2000) = -46d 13' 57.3" with an uncertainty of 5.8 arcseconds (radius, 90% containment). This location is 57 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 99 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 15:50:44.09 = 237.68370 DEC(J2000) = -46:14:06.5 = -46.23513 with a 90%-confidence error radius of about 0.62 arc sec. This position is 9.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.34 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.59. Burst Advocate for this burst is E. Sonbas (eda.sonbas 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: 12160 SUBJECT: GRB 110715A: Swift-BAT refined analysis DATE: 11/07/15 18:25:58 GMT FROM: Scott Barthelmy at NASA/GSFC T. N. Ukwatta (MSU) 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), E. Sonbas (GSFC/USRA/Adiyaman Univ.), M. Stamatikos (OSU), J. Tueller (GSFC), (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 110715A (trigger #457330) (Sonbas, et al., GCN Circ. 12158). The BAT ground-calculated position is RA, Dec = 237.665, -46.237 deg, which is RA(J2000) = 15h 50m 39.7s Dec(J2000) = -46d 14' 13.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 69%. The mask-weighted light curve shows a bright first peak, which is composed of at least 2 overlapping peaks (at the lower energies), starting at ~T-10 sec and peaking at ~T+2.5 sec. the first peak never returns to basline before the second and much weaker peak goes from ~T+12 to T+17 sec. T90 (15-350 keV) is 13.0 +- 4.0 sec (estimated error including systematics). The time-averaged spectrum from T-3.1 to T+20.9 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.25 +- 0.12, and Epeak of 120 +- 21 keV (chi squared 49.6 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.18 +- 0.02 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+1.86 sec in the 15-150 keV band is 53.9 +- 1.1 ph/cm2/sec. To within the calibration limits, the Band model fits equally well. A fit to a simple power law gives a photon index of 1.63 +- 0.03 (chi squared 81.5 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/457330/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12161 SUBJECT: GRB 110715A: Enhanced Swift-XRT position DATE: 11/07/15 18:40:34 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 120 s of XRT Photon Counting mode data and 1 UVOT images for GRB 110715A, 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 = 237.68361, -46.23583 which is equivalent to: RA (J2000): 15h 50m 44.07s Dec (J2000): -46d 14' 09.0" with an uncertainty of 2.2 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: 12162 SUBJECT: GRB 110715A: Swift/UVOT Detection DATE: 11/07/15 22:32:12 GMT FROM: Paul Kuin at MSSL N.P.M. Kuin (MSSL-UCL) and E. Sonbas (GSFC/USRA/Adiyaman Univ.) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110715A 100 s after the BAT trigger (Sonbas et al., GCN Circ. 12158). The preliminary UVOT position is: RA (J2000) = 15:50:44.09 = 237.68369 (deg.) Dec (J2000) = -46:14:06.53 = -46.23515 (deg.) with an estimated uncertainty of 0.56 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 100 249 147 17.37 +/- 0.06 u 312 501 187 17.86 +/- 0.09 b 3734 3857 121 19.5 +/- 0.3 white 3960 4160 197 19.92 +/- 0.16 uvw2 4166 4366 197 >20.1 v 4371 4571 197 19.3 +/- 0.3 uvm2 4576 6211 393 >20.3 uvw1 4781 6280 259 >20.1 u 4986 5186 197 20.1 +/- 0.4 b 5192 5391 197 19.9 +/- 0.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.59 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12164 SUBJECT: GRB110715A: VLT redshift DATE: 11/07/16 05:19:25 GMT FROM: Valerio D'Elia at ASDC S. Piranomonte (OAR/INAF), S. D. Vergani (OAB/INAF), D. Malesani, J. P. U. Fynbo (DARK/NBI), K. Wiersema (Leicester), L. Kaper (Amsterdam) report on behalf of the X-shooter GRB GTO collaboration: We observed the optical afterglow of GRB 110715A (Sonbas et al., GCN Circ. 12158) with the ESO VLT equipped with the X-shooter spectrograph. The optical afterglow is well detected in the R-band acquisition image (taken on Jul 16.06 UT, i.e. 12.3 hr after the GRB), and has a magnitude of R = 18.45 assuming R=15.21 for the USNO-B1 star at RA = 15:50:41.62, Dec = -46:14:25.91. Spectroscopic observations lasted for about 10 minutes, with a mean time 2011 Jul 16.08 UT (12.7 hr after the GRB). The seeing was about 0.9". We then had to interrupt our observations due to strong wind. We detect Ca II and Ca I absorption lines at a common redshift of z=0.82. The wavelength calibration is based on archival calibration files. We acknowledge excellent support from the night astronomer at the VLT, Christophe Martayan, the telescope operator, Claudia Cid, and the shift leader, Jonathan Smoker. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12165 SUBJECT: GRB 110715A: Swift-XRT refined Analysis DATE: 11/07/16 06:54:38 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) and E. Sonbas (GSFC/USRA/Adiyaman Univ.) report on behalf of the Swift-XRT team: We have analysed 4.2 ks of XRT data for GRB 110715A (Sonbas et al. GCN Circ. 12158), from 79 s to 29.4 ks after the BAT trigger. The data comprise 400 s in Windowed Timing (WT) mode (the first 10 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 Evans et al. (GCN. Circ 12161). The light curve can be modelled with an initial power-law decay with an index of alpha=0.57 (+/-0.05), followed by a break at T+2415 s to an alpha of 1.78 (+/-0.13). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.91 (+/-0.07). The best-fitting absorption column is 4.7 (+0.4, -0.3) x 10^21 cm^-2, in excess of the Galactic value of 2.9 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.85 (+/-0.13) and a best-fitting absorption column of 6.0 (+/-0.8) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 5.3 x 10^-11 (8.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.0 (+/-0.8) x 10^21 cm^-2 Galactic foreground: 2.9 x 10^21 cm^-2 Excess significance: 12.6 sigma Photon index: 1.85 (+/-0.13) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00457330. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12166 SUBJECT: Konus-Wind observation of GRB 110715A DATE: 11/07/16 10:11:53 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 110715A (Swift-BAT trigger #457330: Sonbas et al., GCN 12158; Ukwatta et al., GCN 12160) triggered Konus-Wind at T0=47635.304s UT (13:13:55.304) The burst light curve shows a bright pulse, which peaked at T0+2s, and a much weaker pulse at ~T0+11s. A total burst duration is ~20 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110715_T47635/ As observed by Konus-Wind the burst had a fluence of (2.3 ± 0.2)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.984 s, of (1.1 ± 0.1)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+18.432 s) is best fitted in the 20 keV - 10 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha = -1.23 (-0.08, +0.09), the high energy photon index beta = -2.7 (-0.5, +0.2), the peak energy Ep = 120(-11, +12) keV, chi2 = 85.8/84 dof. The spectrum at the maximum count rate (measured from T0+0.256 to T0+2.048 s) is best fitted in the 20 keV - 10 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha = -1.05 (-0.11, +0.11), the high energy photon index beta = -3.6 (<-3.0), the peak energy Ep = 148(-10, +11) keV, chi2 = 51.5/55 dof. Assuming the VLT redshift z = 0.82 (Piranomonte et al., GCN 12164) and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73, the isotropic energy release E_iso is (4.1 ± 0.4)x10^52 erg, the peak luminosity L_iso_max is (3.9 ± 0.2)x10^52 erg/s, and Ep_rest is 220 ± 20 keV. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12168 SUBJECT: GRB 110715A: APEX detection of the submm counterpart DATE: 11/07/17 02:08:00 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (DARK/NBI), A. Lundgren, F. Mac-Auliffe, F.M. Montenegro, D.A. García-Appadoo, I. de Gregorio-Monsalvo, S. Martin, C. De Breuk (ESO), P. Bergman, M. Hajigholi (OSO), C.C. Thoene, J. Gorosabel, A.J. Castro-Tirado (IAA-CSIC), J.P.U. Fynbo (DARK/NBI) and S. Covino (INAF-OAB) report on behalf of a larger collaboration: We have observed the field of GRB 110715A (Sonbas et al. GCN 12158) using LABOCA/APEX at Chajnantor (Chile) in the 870 micrometer band. The weather conditions were good, with a precipitable water vapor of 0.62mm. Observations began on July 16 at 23:21 UT (1.42 days after the burst) and were performed using the photometric mode, centred at the position of the optical counterpart (Kuin et al. GCN 12162, Piranomonte et al. GCN 12164). On a preliminary analysis of 88 minutes on source we detect a flux at the position of the afterglow of 11.0+/-2.3 mJy. Further observations are foreseen. We encourage follow-up in other wavelengths. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12169 SUBJECT: GRB110715A: GROND Detection of the Optical/NIR Afterglow DATE: 11/07/18 17:16:47 GMT FROM: Patricia Schady at MPE/Swift A. C. Updike (NASA/GSFC), P. Schady, J. Greiner (both MPE Garching), T. Kruehler (DARK/NBI), D. A. Kann, S. Klose and A. Rossi (all TLS Tautenburg) report on behalf of the GROND team: We observed the field of GRB 110715A (Swift trigger 457330; Sonbas et al., GCN #12158) 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 00:35 UT on 18th July, lasting just under 2hrs and with a midtime ~3dys after the GRB trigger. They were performed at an average seeing of 1.1" and at an average airmass of 1. We found a single point source within the 2.2" Swift-XRT error circle reported by Evans et al. (GCN #12161), consistent with the UVOT position (Kuin et al., GCN #12162). Based on 4136s of total exposures in g'r'i'z' and 4320s in JHK, we estimate preliminary magnitudes (all AB system) of g' = 22.59 +/- 0.09 r' = 21.22 +/- 0.02 i' = 20.53 +/- 0.02 z' = 19.93 +/- 0.02 J = 19.56 +/- 0.24 H = 18.79 +/- 0.17 K = 18.86 +/- 0.31 Given optical and NIR magnitudes are calibrated against GROND zeropoints and 2MASS field stars, respectively, and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E(B-V)=0.60 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12171 SUBJECT: GRB 110715A: ATCA detection of the radio counterpart DATE: 11/07/19 00:27:05 GMT FROM: Tara Murphy at U.Sydney Paul J. Hancock, Tara Murphy (U of Sydney) and Brian P. Schmidt (ANU) We observed GRB 110715A (GCN 12158) with the Australian Telescope Compact Array (ATCA) on July 18 at 12.2 UT (~3 days after the GRB trigger). We find a single unresolved radio source consistent with the UVOT position (GCN 12162). The source has a measured flux density of 2.4 +/- 0.1 mJy/beam at 44.00 GHz. Further observations are planned. We thank the observatory staff for scheduling and supporting these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12174 SUBJECT: GRB 110715A optical observations DATE: 11/07/19 12:16:46 GMT FROM: AAVSO GRB Network at AAVSO Peter Nelson (Ellinbank, Victoria, Australia) reported to the AAVSO International High Energy Network the following optical observations of GRB 110715A (Sonbas et al., GCN #12158): P. Nelson (Ellinbank Observatory, Ellinbank, VIC, Australia) reports a detection of GRB 110715A from fifteen frames of 30-seconds exposure each taken with a clear filter through a 0.32-cm PlaneWave f/8 CDK and SBIG ST8XE camera. The magnitude derived from all frames is m(CR) = 18.0 +/- 0.2 at the mid-point exposure time of 2011 July 15 14:05:01 UT. Magnitudes were measured relative to the USNO-B1.0 comparison star at RA: 15:50:41.62, Decl: -46:14:25.91 with magnitude R=15.21 (see Piranomonte et al., GCN #12164). Nelson reports that time-series was obtained by averaging the 15 frames into three consecutive groups of five frames, yielding the following magnitudes: Time (UT) Mag (Clear, R zeropoint) 13:54:23 18.01 +/- 0.18 14:05:28 17.93 +/- 0.15 14:15:12 18.47 +/- 0.25 The position derived from these images is RA: 15:50:44.07, Decl: -46:14:06.5, which is fully consistent with the optical position given by Kuin et al. (GCN #12162). The AAVSO International High Energy Network was made possible through grants from the Charles Curry Foundation and from NASA. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12184 SUBJECT: GRB 110715A : Suzaku WAM observation of the prompt emission DATE: 11/07/20 02:05:47 GMT FROM: Norisuke Ohmori at Miyazaki U N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki), K. Yamaoka (Aoyama Gakuin U.), M. Ohno, Y. Hanabata, T. Uehara, T. Takahashi, M. Mizuno, Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya U.), T. Yasuda, Y. Terada, W. Iwakiri, K. Takahara, M. Asahina, S. Kobayashi, M. Tashiro (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 GRB 110715A (Swift/BAT trigger #457330 ; Sonbas et al., GCN 12158) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 13:13:49.914 UT (=T0). The observed light curve shows a multi-peaked structure starting at T0, ending at T0+4s, followed by a weaker emission seen up to T0+20s with a duration (T90) of 8 seconds. The fluence in 100 - 1000 keV was 1.28 (-0.06, +0.07) x10^-5 erg/cm^2. The 1-s peak flux measured from T0+3s was 20.3 (-1.1, +1.0) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-3s to T0+20s is well fitted by a single power-law with a photon index of 2.67 (-0.18, +0.19) (chi^2/d.o.f = 24.0/15). All the quoted errors are at statistical 90% confidence level. The light curves for this burst will be available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12185 SUBJECT: GRB110715A: spectral lag analysis DATE: 11/07/20 13:34:29 GMT FROM: Dong Xu at Weizmann Inst D. Xu (WIS) reports: GRB 110715A was detected by Swift/BAT (Sonbas et al., GCN 12158; Ukwatta et al., GCN 12160), Konus-Wind (Golenetskii et al., GCN 12166), and Suzaku/WAM (Ohmori et al., GCN 12184). The prompt emission of this burst has a high photon count rate. And the lightcurve shows a multi-peaked structure lasting ~5s (i.e., T0+5s, where T0 is the trigger time), followed by a much weaker emission up to ~T0+20s. Therefore, the overall T90 duration is ~10s or even a bit longer. On the other hand, such a lightcurve feature is reminiscent of previous short bursts with extended tail emissions. With the redshift z = 0.82 (Piranomonte et al., GCN 12164) and the cosmological parameters H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73, the isotropic energy release E_iso is (4.1 ± 0.4)x10^52 erg, the isotropic peak luminosity L_iso,p is (3.9 ± 0.2)x10^52 erg/s, and the rest-frame \nu_F\nu peak energy Ep_rest is 220 ± 20 keV (Golenetskii et al., GCN 12166). Thus, the values of Eiso and Ep_rest are well consistent with the Eiso-Ep_rest relation (i.e., Amati relation) for long GRBs (or collapsar bursts). The Swift/BAT data were reduced in a standard way and a CCF method was used to derive spectral lags upon the lightcurves with 0.064s binning (Xu et al., ApJ, 696, 971). We found lags of 0.04+/-0.01s (1sigma) for 15-25 V.S. 25-50 keV and 0.04+/-0.01 (1sigma) for 50-75 V.S. 75-350 keV. Thus, this event also fits the Liso-spectral lag relation for long GRBs. At z=0.82, searching for an accompanying SN is doable but requires very deep photometric follow-ups (ref. Tanvir et al., ApJ, 725, 625).