//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15112 SUBJECT: GRB 130822A: Swift detection of a short burst DATE: 13/08/22 16:12:35 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT D. Kocevski (NASA/GSFC/ORAU), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), V. Mangano (PSU), F. E. Marshall (NASA/GSFC), C. Pagani (U Leicester), K. L. Page (U Leicester), J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), R. L. C. Starling (U Leicester) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift Team: At 15:54:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130822A (trigger=567163). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 27.940, -3.219 which is RA(J2000) = 01h 51m 46s Dec(J2000) = -03d 13' 08" 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 0.1 sec. The peak count rate was ~3700 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 15:55:30.7 UT, 73.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 27.9218, -3.2085 which is equivalent to: RA(J2000) = 01h 51m 41.22s Dec(J2000) = -03d 12' 30.6" with an uncertainty of 3.1 arcseconds (radius, 90% containment). This location is 75 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.76 x 10^20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 250 seconds with the U filter starting 294 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 expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is D. Kocevski (daniel.kocevski 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: 15114 SUBJECT: GRB 130822A: Weihai optical upper limit DATE: 13/08/22 18:32:54 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), D.-Y. Ren, C. Cao, S.-M. Hu (SDU) report: We observed the field of GRB 130822A (Kocevski et al., GCN 15112) using the 1m telescope located in Weihai, Shandong, China. Observations started at 17:05:49 UT on 2013-08-22 (i.e., 1.19 hr after the BAT trigger) and 3x500s SDSS r'-band frames were obtained in a cloudy weather. No optical source is detected within the XRT error circle (Kocevski et al., GCN 15112) in the stacked image down to r'>~20 mag, calibrated with SDSS field. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15116 SUBJECT: GRB 130822A, Swift-BAT refined analysis DATE: 13/08/23 01:23:49 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), D. Kocevski (NASA/GSFC/ORAU), 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), (i.e. the Swift-BAT team): Using the data set from T-60 to T+123 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130822A (trigger #567163) (Kocevski, et al., GCN Circ. 15112). The BAT ground-calculated position is RA, Dec = 27.931, -3.193 deg which is RA(J2000) = 01h 51m 43.4s Dec(J2000) = -03d 11' 34.0" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 92%. The mask-weighted light curve shows a single peak. T90 (15-350 keV) is 0.04 +- 0.01 sec (estimated error including systematics). The time-averaged spectrum from T-0.004 to T+0.044 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.64 +- 0.29. The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-08 erg/cm2. The 1-sec peak photon flux measured from T-0.48 sec in the 15-150 keV band is 0.3 +- 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/567163/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15117 SUBJECT: GRB 130822A: Enhanced Swift-XRT position DATE: 13/08/23 02:28:29 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 465 s of XRT Photon Counting mode data and 1 UVOT images for GRB 130822A, 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 = 27.92181, -3.20865 which is equivalent to: RA (J2000): 01h 51m 41.23s Dec (J2000): -03d 12' 31.1" with an uncertainty of 2.6 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. 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: 15118 SUBJECT: GRB 130822A: Swift/UVOT Upper Limits DATE: 13/08/23 09:44:03 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and D. Kocevski (NASA/GSFC/ORAU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130822A 81 s after the BAT trigger (Kocevski et al., GCN Circ. 15112). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 15117) 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 white_FC 81 231 147 >20.8 u_FC 295 544 246 >20.7 white 81 1543 392 >21.4 v 624 1420 97 >19.3 b 550 1170 58 >20.1 u 295 1145 265 >20.9 w1 674 1470 97 >19.7 w2 600 620 19 >19.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15119 SUBJECT: GRB 130822A: WHT ACAM observations DATE: 13/08/23 12:00:09 GMT FROM: Klaas Wiersema at U Leicester K. Wiersema (Leicester), A. Levan (Warwick), D. Malesani (DARK) report on behalf of a larger collaboration: We observed the position of short GRB 130822A (Kocevski et al., GCN 15112) using the 4.2m William Herschel Telescope with the ACAM instrument and a Sloan r filter. We do not identify a source in or near the refined XRT error circle (Beardmore et al., GCN 15117) in a dataset of 20x50 seconds exposures (0.365 days after burst), taken under poor weather conditions. An upper limit of r=21.9 is found at the XRT position. We note the presence of a moderately bright galaxy (r=18.15) offset approximately 22" from the GRB location and with a photometric redshift of z=0.1. If associated with would correspond to an offset of 40 kpc. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15120 SUBJECT: GRB 130822A: Swift-XRT refined Analysis DATE: 13/08/23 12:12:03 GMT FROM: Phil Evans at U of Leicester A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), J.A. Kennea (PSU), V. Mangano (PSU), M.C. Stroh (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB) and D. Kocevski report on behalf of the Swift-XRT team: We have analysed 7.2 ks of XRT data for GRB 130822A (Kocevski et al. GCN Circ. 15112), from 85 s to 41.0 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 15117). The source is fading with alpha >0.5. If the light curve continues to decay with a power-law decay index of , the count rate at T+24 hours will be 2.8 x 10^-5 count s^-1 The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00567163. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15121 SUBJECT: GRB 130822A: Gemini Observations DATE: 13/08/23 20:43:44 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (NASA / GSFC), D. A. Perley (Caltech), A. Cucchiara (UCSC), W. Fong (CfA), and A. J. Levan (U. Warwick) report on behalf of a larger collaboration: We have imaged the location of the X-ray afterglow (Beardmore et al., GCN 15117) of the short GRB 130822A (Kocevski et al., GCN 15112) with the Gemini Multi-Object Spectrograph on the 8 m Gemini North telescope. We obtained a total integration of 600 s in the i' filter beginning at 12:56 UT on 23 August 2013 (0.88 d after the Swift trigger). We detect no sources within the enhanced XRT error circle. Using nearby point sources from SDSS for calibration, we calculate an upper limit of i' > 24.5 mag at this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15122 SUBJECT: GRB 130822A: 5.8 GHz VLA upper limit DATE: 13/08/24 00:46:26 GMT FROM: Wen-fai Fong at CFA W. Fong, B. A. Zauderer and E. Berger (Harvard) report: "We observed the field of the short-duration GRB 130822A (Kocevski et al., GCN 15112) with the Karl G. Jansky Very Large Array (VLA) beginning on 2013 Aug 23.33 UT (15.9 hr post-burst) at a mean frequency of 5.8 GHz. In 1 hour of observations, we do not detect any radio source within or around the XRT position (Beardmore et al., GCN 15117). We therefore place a 3-sigma limit of ~30 microJy on the radio afterglow of GRB 130822A at 15.9 hr after the burst. We thank the VLA staff for quickly executing these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15126 SUBJECT: GRB 130822A Swift-BAT Spectral lag analysis DATE: 13/08/27 01:32:20 GMT FROM: Takanori Sakamoto at AGU J. Norris (BSU), S. D. Barthelmy (GSFC), T. Sakamoto (AGU), N. Gehrels (GSFC) We report the spectral lag analysis for GRB 130822A (Kocevski, et al., GCN Circ. 15112) based on the BAT data. Using 1-ms binned light curve, the spectral lag for the 15-25 keV to 50-100 keV bands is 2.6 (+3.5/-3.2) ms. Since the lag value is consistent with zero, we believe this burst belongs to a short burst category. There is no evidence for extended emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15137 SUBJECT: GRB 130822A: optical upper limits DATE: 13/08/30 13:20:03 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (IKI), R.Inasaridze (AAO), O. Kvaratskhelia (AAO), V. Ayvazian(AAO), Yu. Krugly (IA KhNU), I. Slyusarev (IA KhNU), I. Molotov (KIAM), V. Linkov (ISON), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift GRB 130822A (Kocevski et al., GCN 15112) on Aug., 22 with AS-32 (0.7m) telescope of Abastumani Observatory, SANTEL-400AN (0.4m) telescope of ISON-Kislovodsk observatory, and AZT-8 (0.7m) telescope of Institute of Astronomy, Kharkiv National University. We obtained several unfiltered frames with exposures of 120 s (AS-32), 100 s and 60 s (SANTEL-400AN), and several frames with filter R with exposure of 120 s (AZT-8). Within the enhanced XRT circle (Beardmore et al., GCN 15117) we did not detect any source on stacked images. The details of the photometry are the following: Telescope t_start, UT filter exptime,s t-t0, mid, days uplim AZT-8 21:39:21 R 55*120 0.28000 20.6 S-400 22:31:37 None 23*100 0.30332 19.3 AS-32 23:46:59 None 40*120 0.36513 21.9 The photometry is based on SDSS stars, R mag (R mag obtained via transformations ugriz in BVRI (Lupton, 2005): SDSS id R R_err J015202.75-031421.9 12.80 0.012 J015134.64-031348.8 13.95 0.013 J015148.69-030854.9 14.62 0.013 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15178 SUBJECT: GRB 130822A: nearby galaxy redshifts DATE: 13/09/04 18:40:36 GMT FROM: Klaas Wiersema at U Leicester K. Wiersema (Leicester), A. Levan (Warwick), S. B. Cenko (NASA/GSFC) and N. Tanvir (Leicester) report on behalf of a larger collaboration: We acquired spectroscopy of two galaxies close to the afterglow position of short GRB 130822A (Kocevski et al. GCN 15112), these galaxies have low chance coincidence probability values (note that there are no sources found within the XRT error circle, Cenko et al. GCN 15121). These two galaxies, hereafter named G1 and G2, are located at approximate positions (SDSS DR10): G1 RA: 01:51:42.66 Dec: -03:12:25.48 G2 RA: 01:51:41.09 Dec: -03:11:07.47 A finder chart showing the locations of these galaxies (Gemini i' band; Cenko et al. GCN 15121) can be found here: http://www.star.le.ac.uk/~kw113/G1G2.png We acquired spectroscopy with ACAM on the William Herschel Telescope (directly following the photometry observations reported in Wiersema et al. GCN 15119) and GMOS on Gemini-North (starting at 13:35 UT on 2 September 2013). In both cases the slit was aligned such that both galaxies were covered simultaneously by the slit. The ACAM spectrum covers the range 3500-9400, the Gemini spectrum the range 3850-6730 A. Galaxy G1 shows strong absorption complexes (G band, Mg b triplet, Fe 4668, Ca II) as well as a single, weak, emission line (H beta), at a common redshift z=0.154. Galaxy G2 shows stronger emission lines of H alpha and H beta, as well as absorption complexes (G band, Na I, Mg b triplet) at a common redshift z=0.045. At these redshifts, the offset from the afterglow to galaxy G1 is 58 kiloparsec, and to G2 72 kiloparsec. If the brighter, but somewhat further offset, galaxy G2 is the host galaxy, it would place GRB 130822A within the Advanced LIGO / Virgo horizon.