//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12600 SUBJECT: GRB 111129A: Swift detection of a burst with an optical counterpart DATE: 11/11/29 16:27:24 GMT FROM: Scott Barthelmy at NASA/GSFC J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), P. A. Evans (U Leicester), 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), K. L. Page (U Leicester), D. M. Palmer (LANL), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), M. C. Stroh (PSU), C. A. Swenson (PSU), E. Troja (NASA/GSFC/ORAU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 16:18:14 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 111129A (trigger=508712). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 307.441, -52.724, which is RA(J2000) = 20h 29m 46s Dec(J2000) = -52d 43' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a few weak peaks with a total duration of about 20 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 16:19:46.5 UT, 92.2 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 307.43460, -52.71300 which is equivalent to: RA(J2000) = 20h 29m 44.30s Dec(J2000) = -52d 42' 46.8" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 42 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 3.24 x 10^20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 95 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 20:29:44.15 = 307.43395 DEC(J2000) = -52:42:46.5 = -52.71291 with a 90%-confidence error radius of about 0.64 arc sec. This position is 1.4 arc sec. from the center of the XRT error circle. The estimated magnitude is 19.06 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. Burst Advocate for this burst is J. L. Racusin (judith.racusin 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: 12601 SUBJECT: GRB 111129A: Enhanced Swift-XRT position DATE: 11/11/29 20:10:37 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 809 s of XRT Photon Counting mode data and 1 UVOT images for GRB 111129A, 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 = 307.43385, -52.71297 which is equivalent to: RA (J2000): 20h 29m 44.12s Dec (J2000): -52d 42' 46.7" with an uncertainty of 1.9 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: 12602 SUBJECT: GRB 111129A: Swift-BAT refined analysis DATE: 11/11/30 00:47:25 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), J. L. Racusin (NASA/GSFC), 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-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 111129A (trigger #508712) (Racusin, et al., GCN Circ. 12600). The BAT ground-calculated position is RA, Dec = 307.415, -52.722 deg, which is RA(J2000) = 20h 29m 39.5s Dec(J2000) = -52d 43' 20.9" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 61%. The mask-weighted light curve shows two slightly overlapping peaks starting at ~T-7 sec, peaking at ~T-5 and T+1 sec, and ending at ~T+10 sec. T90 (15-350 keV) is 7.6 +- 1.4 sec (estimated error including systematics). The time-averaged spectrum from T-6.29 to T+2.88 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.56 +- 0.38. The fluence in the 15-150 keV band is 1.8 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.41 sec in the 15-150 keV band is 0.9 +- 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/508712/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12604 SUBJECT: GRB 111129A: Swift-XRT refined Analysis DATE: 11/11/30 05:27:05 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), V. Mangano (INAF-IASFPA) and J.L. Racusin report on behalf of the Swift-XRT team: We have analysed 9.2 ks of XRT data for GRB 111129A (Racusin et al. GCN Circ. 12600), from 77 s to 34.7 ks after the BAT trigger. The data comprise 26 s in Windowed Timing (WT) mode (the first 8 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 Osborne et al. (GCN. Circ 12601). The light curve can be modelled with an initial power-law decay with an index of alpha=0.57 (+0.16, -0.17), followed by a break at T+3006 s to an alpha of 1.19 (+0.12, -0.11). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.93 (+/-0.08). The best-fitting absorption column is 1.72 (+0.40, -0.24) x 10^21 cm^-2, in excess of the Galactic value of 3.2 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 4.0 x 10^-11 (5.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.72 (+0.40, -0.24) x 10^21 cm^-2 Galactic foreground: 3.2 x 10^20 cm^-2 Excess significance: 11.6 sigma Photon index: 1.93 (+/-0.08) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00508712. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12605 SUBJECT: GRB 111129A, GROND afterglow observations DATE: 11/11/30 09:34:58 GMT FROM: Andrea Rossi at TLS Tautenburg A. Rossi, A. Nicuesa Guelbenzu (all Tautenburg) and J. Greiner (MPE) report on behalf of the GROND team: We observed the field of GRB 111129A (Racusin, GCN 12600) 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 on La Silla. Observations started at 00:30 UT on November 30, about 8.2 hr after the burst, and continued for about 2 hrs. They were performed at an average seeing of 1 arcsec and an average airmass of 1.8. We detect the afterglow discovered by Racusin et al. (GCN 12600) in the optical/NIR. At a mean time of November 30, 01:31 UT (9.25 hours after the trigger) with exporures times of 24.3 minutes in griz and 20 min in JHK, we measure the following preliminary magnitudes (AB system): g' = 22.9 +/- 0.1, r' = 22.3 +/- 0.1, i' = 21.8 +/- 0.1, z = 21.3 +/- 0.1, J = 20.5 +/- 0.2, H = 19.8 +/- 0.2, K = 19.1 +/- 0.3 Optical data are calibrated against GROND zeropoints and NIR against 2MASS field stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12606 SUBJECT: GRB 111129A: Swift/UVOT Detection DATE: 11/11/30 10:47:24 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL-UCL) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 111129A 96 s after the BAT trigger (Racusin et al., GCN Circ. 12600). A source consistent with the XRT position (Osborne et al., GCN Circ. 12601) is detected in the initial UVOT exposures in the white and u filters. The source had already faded by the time the other filters were used. The preliminary UVOT position is: RA (J2000) = 20:29:44.15 = 307.43396 (deg.) Dec (J2000) = -52:42:46.5 = -52.71293 (deg.) with an estimated uncertainty of 0.54 arc sec. (radius, 90% confidence). 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 96 245 147 19.11 ± 0.1 white 534 726 39 >20.32 v 584 12305 524 >19.9 b 509 16631 1223 >21.3 u 254 503 246 19.10 ± 0.16 w1 633 22753 1296 >21.2 m2 608 6008 413 >20.4 w2 559 12186 1120 >21.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).