//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15578 SUBJECT: GRB 131205A: Swift detection of a burst DATE: 13/12/05 09:40:23 GMT FROM: Kim Page at U.of Leicester T. N. Ukwatta (MSU), V. D'Elia (ASDC), C. B. Markwardt (NASA/GSFC), A. Melandri (INAF-OAB), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 09:18:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 131205A (trigger=580267). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 131.609, -60.174 which is RA(J2000) = 08h 46m 26s Dec(J2000) = -60d 10' 25" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiple peaked structure with a duration of about 60 sec. The peak count rate was ~1300 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 09:20:07.5 UT, 88.7 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 131.6276, -60.1556 which is equivalent to: RA(J2000) = 08h 46m 30.63s Dec(J2000) = -60d 09' 20.0" with an uncertainty of 2.7 arcseconds (radius, 90% containment). This location is 74 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 1.50 x 10^21 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 93 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. Data from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.26. We note that the spacecraft star tracker was out of lock during a portion of this GRB, but we believe the burst is real. The position may be revised after further processing. Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 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: 15579 SUBJECT: GRB 131205A: Zadko observatory - Gingin optical observations DATE: 13/12/05 14:28:19 GMT FROM: Alain Klotz at IRAP-CNRS-OMP A. Klotz (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), D. Turpin (IRAP-CNRS-OMP), B. Gendre , M. Boer, K. Siellez, H. Dereli , O. Bardho (UNS-CNRS-OCA), A. Williams (PO-UWA), R. Martin (PO-UWA) report: We imaged the field of GRB 131205A detected by SWIFT (trigger 580267) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 3.74h after the GRB trigger which occured during Australian day time. The elevation of the field increased from 19 degrees above horizon and weather conditions were excellent. We co-added a series of exposures but we do not detect any OT with a limiting magnitude of: t0+3.74h to t0+4.45h : Rlim = 20.2 Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15580 SUBJECT: GRB 131205A: Enhanced Swift-XRT position DATE: 13/12/05 15:16:19 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 2064 s of XRT Photon Counting mode data and 3 UVOT images for GRB 131205A, 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 = 131.62784, -60.15601 which is equivalent to: RA (J2000): 08h 46m 30.68s Dec (J2000): -60d 09' 21.6" with an uncertainty of 2.0 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: 15581 SUBJECT: GRB 131205A: Swift/UVOT Upper Limits DATE: 13/12/05 17:40:58 GMT FROM: Craig Swenson at PSU/Swift C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 131205A 94 s after the BAT trigger (Ukwatta et al., GCN Circ. 15578). No optical afterglow consistent with the enhanced XRT position (Beardmore et al. GCN Circ. 15580) is detected in the initial UVOT exposures. Because the spacecraft attitude was not stable during the first finding chart exposure, we do not report on that exposure here. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the second finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u_FC 306 556 246 >20.8 white 586 12884 1171 >21.7 v 636 6778 471 >20.5 b 561 12313 1160 >21.5 u 306 11400 1386 >22.0 w1 685 7121 385 >20.4 m2 660 6983 471 >20.4 w2 611 6574 471 >20.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.26 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15583 SUBJECT: GRB 131205A: Swift-XRT refined Analysis DATE: 13/12/05 21:40:04 GMT FROM: Phil Evans at U of Leicester P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), V. Mangano (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and T.N. Ukwatta report on behalf of the Swift-XRT team: We have analysed 10 ks of XRT data for GRB 131205A (Ukwatta et al. GCN Circ. 15578), from 226 s to 24.4 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 15580). The light curve can be modelled with a power-law decay with a decay index of alpha=1.10 (+0.09, -0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 (+/-0.4). The best-fitting absorption column is 3.2 (+1.4, -1.2) x 10^21 cm^-2, in excess of the Galactic value of 1.5 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.2 (+1.4, -1.2) x 10^21 cm^-2 Galactic foreground: 1.5 x 10^21 cm^-2 Excess significance: 2.3 sigma Photon index: 2.1 (+/-0.4) If the light curve continues to decay with a power-law decay index of 1.10, the count rate at T+24 hours will be 9.9 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.8 x 10^-14 (6.7 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00580267. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15584 SUBJECT: GRB 131205A: Swift-BAT refined analysis DATE: 13/12/05 22:11:19 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+771 sec from the recent telemetry downlink, we report further analysis of BAT GRB 131205A (trigger #580267) (Ukwatta, et al., GCN Circ. 15578). The BAT ground-calculated position is RA, Dec = 131.573, -60.181 deg which is RA(J2000) = 08h 46m 17.6s Dec(J2000) = -60d 10' 51.5" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 95%. The mask-weighted light curves two peaks starting at ~T-5, peaking at ~T+1, and ending at ~T+5 sec, and the second peak from ~T+18 to ~T+22 sec. T90 (15-350 keV) is 37.5 +- 9.6 sec (estimated error including systematics). The time-averaged spectrum from T-18.50 to T+20.41 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.57 +- 0.38. The fluence in the 15-150 keV band is 2.9 +- 0.7 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+19.30 sec in the 15-150 keV band is 0.6 +- 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/580267/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15585 SUBJECT: GRB131205A : GROND Observations DATE: 13/12/06 17:35:52 GMT FROM: Karla Varela at MPE S. Schmidl (TLS Tautenburg ), K. Varela and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of the GRB 131205A (Ukwatta et al., GCN #15578) simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at La Silla Observatory (Chile). Observations started at 05:07 UT on 06 December 2013, 19.5 hours after the GRB. They were performed at an average seeing of 1.0" and at an average airmass of 1.3. Based on six co-added observations with individual exposure times of 1500s in g'r'i'z' and 1200s in JHK, we do not detect any source inside the enhanced XRT error circle (Beardmore et al., GCN #15580) down to preliminary 3 sigma limiting magnitudes (all in the AB system) : g' > 25.8 mag, r' > 25.6 mag, i' > 24.9 mag, z' > 24.5 mag, J > 22.1 mag, H > 21.5 mag, K > 20.8 mag. Magnitudes are calibrated against GROND zeropoints (griz) and 2MASS stars (JHK), and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.25 mag in the direction of the burst (Schlegel et al. 1998). We note the marginal detection of a source, located 1.9" from the center of the XRT circle, at RA : 08:46:30.86 DEC : -60:09:20.6, with an uncertainty of 0.2 arcsec and magnitudes of r = 24.8 +/- 0.2 i = 24.7 +/- 0.3 z = 24.3 +/- 0.3. This is consistent with a power law and thus could be the afterglow of GRB131205A, but no statement can be made about fading at this time. Follow-up observations are required to determine the nature of this source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15595 SUBJECT: GRB 131205A: GROND confirmation of afterglow DATE: 13/12/13 12:39:29 GMT FROM: Jochen Greiner at MPI K. Varela, D.A. Kann and J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed again the field of the GRB 131205A (Ukwatta et al., GCN #15578) simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at the La Silla Observatory (Chile). Observations started at 05:22 UT on 11 December 2013. They were performed at an average seeing of 0.7 arcsec and at an average airmass of 1.3. Based on four co-added observations with individual exposure times of 2214s in g'r'i'z' and 1800s in JHKs, we measure for the source at the border of the X-ray error circle (Beardmore et al., GCN #15580), which was proposed as potential counterpart (Schmidl et al. 2013, GCN #15585), the following magnitudes: r' = 26.5 +/- 0.4 i' = 25.3 +/- 0.4 Compared to our earlier measurements of r' = 24.8+/-0.2, i' = 24.7+/-0.3 this implies a fading of 1.7+/-0.5 in r', and 0.6+/-0.5 in i'. We conclude that the fading in r' is significant, and propose this source as the optical counterpart of GRB 131205A. The low amplitude in the i'-band may be caused by the emergence of light from a red host galaxy. Observations with bigger glasses are required to verify this interpretation. Note that the above r'i' magnitudes are calibrated against GROND zeropoints and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.25 mag in the direction of the burst (Schlegel et al. 1998).