//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12253 SUBJECT: GRB 110807A: Swift detection of a burst or a posible new SGR DATE: 11/08/07 20:22:17 GMT FROM: Scott Barthelmy at NASA/GSFC V. D'Elia (ASDC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), M. M. Chester (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), C. J. Saxton (UCL-MSSL), G. Stratta (ASDC), C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 19:57:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110807A (trigger=458907). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 278.696, -8.760 which is RA(J2000) = 18h 34m 47s Dec(J2000) = -08d 45' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single timebin spike structure with a duration of less than 0.064 sec. The peak count rate was ~3500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 20:03:13.2 UT, 326.8 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source located at RA, Dec 278.71751, -8.76597 which is equivalent to: RA(J2000) = 18h 34m 52.20s Dec(J2000) = -08d 45' 57.5" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 79 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 6.6 arcseconds from that of a known X-ray source: 2XMM J183452.4-084603 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 150 seconds with the White filter starting 332 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. Due to the short, soft nature of the burst, and the proximity of the source to the Galactic plane (0.3 degrees) we suggest that this source may be a previously unknown Soft Gamma Repeater. Verification of this could come if a second burst is seen or the XRT counterpart shows periodicity. 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: 12254 SUBJECT: GRB 110807A: SAO RAS observations DATE: 11/08/08 01:05:50 GMT FROM: Vladimir Sokolov at SAO RAS A. S. Moskvitin, V. V. Sokolov and R. I. Uklein, report on behalf of the SAO RAS GRB follow-up team: We observed the field of GRB 110807A (D'Elia et al, GCN 12253) with the 6-meter BTA + Scorpio on August 7.843 -- 7.857 UT (observations were started since 16 minutes after the BAT trigger). We obtained 21 x 30 sec. exposures in Rc band. At our stacked image (seeing = 1".9), inside the XRT error circle we clearly detected only one object with the following coordinates: R. A. = 18:34:52.42 Dec. = -08:45:57.08, with approximately error 1" (all coordinates for Epoch = 2000). The brightness of the object were measured as R = 23.44 +/- 0.34 (no extinction correction were made). Calibration were done against the magnitude R2 = 17.85 of the USNO-B.1 star 0812-0420010 (R.A. = 18:34:51.24, Dec. = -08:45:40.1). We also noted presence of the other object just outside from the XRT error circle to the North-West which is marked as USNO-B.1 star 0812-0420027 (R.A. = 18:34:51.86, Dec. = -08:45:52.3). At our image this object is extended along the South-East direction and probably may be two or more objects. Zoomed image from BTA can be found at ftp://ftp.sao.ru/pub/grb/GRB110807A/GRB110807A_BTA.jpeg The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12266 SUBJECT: SGR 1834.9-0846/ GRB 110807A: archival IR observations DATE: 11/08/10 12:58:34 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester) report: "The region around the newly discovered SGR 1834.9-0846 (D'Elia et al. GCN 12253; Barthelmy et al. GCN 12259) has been imaged as part of the UKIDSS Galactic Plane Survey (Lucas et al. 2008 MNRAS 391 136) in the J, H and K-bands on May 10, 2007. Close to the refined XRT location (current 90% error radius 1.8") we find two sources. One at: RA(J2000) 18:34:52.17 DEC(J2000) -08:45:54.0 which is also in 2MASS, and has catalogue magnitudes of J=16.41 +/- 0.01, H=14.96 +/- 0.01, K= 14.13 +/- 0.01. We however note that this source appears marginally extended in the K-band imaging, and may be the result of the superposition of two sources within this crowded region. The second source is at location: RA(J2000) 18:34:52.02 DEC(J2000) -08:45:54.5 and has magnitudes of J=17.73 +/- 0.03, H=16.67 /- 0.02, K=16.07+/- 0.04. There are also numerous faint sources at larger offsets from the refined XRT position. Further observations will be needed to ascertain if any of these sources exhibit photometric variability." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12272 SUBJECT: SGR 1834.9-0846/ GRB 110807A, I-band observations DATE: 11/08/11 11:59:50 GMT FROM: Juan Carlos Tello at IAA-CSIC J. C. Tello, A. Sota and A. J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report: "We observed SGR 1834.9-0846/ GRB 110807A detected by Swift/BAT (D'Elia et al., GCNC 12253, Barthelmy, GCN 12259) with the OSN 1.5m telescope. I-band frames were obtained on 7 Aug, starting 16 min after the gamma-ray detection (i.e. simultaneously to the BTA Rc-band observations, Moskvitin et al., GCNC 12254). Neither on the single I-band images (10s exposure time each) nor on the co-added frames, taken between 20:14 and 21:48 UT, with total exposure 4820 sec, an object is detected within the Swift/XRT error box. The limiting magnitude for the combined image is I = 21.6 (calibrated against USNO B1.0)." This message may be cited.