//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13875 SUBJECT: GRB 121017A: Swift detection of a burst DATE: 12/10/17 19:55:10 GMT FROM: Scott Barthelmy at NASA/GSFC D. Grupe (PSU), B. N. Barlow (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), E. A. Helder (PSU), S. T. Holland (STScI), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 19:23:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 121017A (trigger=536172). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 288.816, -1.595 which is RA(J2000) = 19h 15m 16s Dec(J2000) = -01d 35' 43" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows at least two peaks with a duration of about 10 sec (possibly longer). The peak count rate was ~2500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 19:25:03.3 UT, 95.2 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 288.8302, -1.6042 which is equivalent to: RA(J2000) = 19h 15m 19.25s Dec(J2000) = -01d 36' 15.1" with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 60 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.22 x 10^21 cm^-2, Kalberla et al. 2005), with an excess column of 3 (+2.89/-2.40) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 1141 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. There is no new source down to a limit of about 19th mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.44. XRT and UVOT detections were delayed due to entry into the SAA shortly after the initial trigger. Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). 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: 13876 SUBJECT: GRB 121017A: BOOTES-2/TELMA observations DATE: 12/10/17 20:34:07 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia GRB 121017A: BOOTES-2/TELMA observations M. Jelínek, A. J. Castro-Tirado, J. Gorosabel (IAA-CSIC Granada), S. Guziy (Nikolaev Univ.), O. Rabaza (Univ. de Granada), on behalf of a larger collaboration, report: “Following the detection of GRB 121017A by Swift (Grupe et al. GCN Circ. 13875) the 0.6m TELMA robotic telescope (+ COLORES) in Málaga (Spain) started to take images (unfiltered) about 3 min postburst (19:26:10 UT), following the initial BAT position. There is no optical counterpart within the Swift/X-ray error box down to R = 18.5 for a 153s combined exposure (5 min post burst). Further exposures in i’-band (22:05 UT, 1200s on the aggregate) set a limit of 19.5 (35 min post burst). We note the considerable extinction (A_v = 1.4) towards this direction 6 deg below the Galactic Plane. Observations are ongoing.” [GCN OPS NOTE(17oct12): Per author's request, OR was added to the author list.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13877 SUBJECT: GRB 121017A optical observations DATE: 12/10/17 21:48:00 GMT FROM: Alina Volnova at SAI MSU A. A. Volnova (SAI MSU, IKI RAS), A. S. Moskvitin (SAO RAS) on behalf of larger collaboration, reports We observed the field of GRB 121017A (Grupe et al., GCN Circ. 13875) with the 1-m Zeiss-1000 telescope of SAO RAS in Rc band. The weather conditions were good, airmass = 5 - 6, seeing = 2.6". Observations were started since 9.5 minutes after the BAT trigger, middle time t-t0 = 0.01407 days. We do not detect any object in the XRT error circle down to a limiting magnitude 18.8 as well as Jelínek et al. (GCN Circ. 13876). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13878 SUBJECT: GRB 121017A: 1.23m CAHA R-band observations DATE: 12/10/18 00:31:03 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC, Granada), S. Mottola (DLR, Berlin), report on behalf of a larger collaboration: "We imaged the field of the Swift GRB 121017A (Grupe et al., GCN Circ. 13875) with the 1.23m Calar Alto telescope. The observations were carried out in the R-band on Oct. 17.85440--17.86153 UT (1.11--1.29 hours post burst) with a total exposure time of 2x300s. No optical source brighter than R~20 was found within the XRT error circle." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13879 SUBJECT: GRB 121017A: Enhanced Swift-XRT position DATE: 12/10/18 00:37:34 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 388 s of XRT Photon Counting mode data and 1 UVOT images for GRB 121017A, 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 = 288.83026, -1.60418 which is equivalent to: RA (J2000): 19h 15m 19.26s Dec (J2000): -01d 36' 15.0" 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: 13880 SUBJECT: GRB 121017A: Swift-BAT refined analysis DATE: 12/10/18 02:26:15 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), E. E. Fenimore (LANL), N. Gehrels (GSFC), D. Grupe (PSU), H. A. Krimm (GSFC/USRA), 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-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 121017A (trigger #536172) (Grupe, et al., GCN Circ. 13875). The BAT ground-calculated position is RA, Dec = 288.820, -1.602 deg, which is RA(J2000) = 19h 15m 16.8s Dec(J2000) = -01d 36' 07.3" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve a single peak starting at ~T-3 sec, peaking at ~T+1 sec, and ending at ~T+5 sec. T90 (15-350 keV) is 4.2 +- 0.5 sec (estimated error including systematics). The time-averaged spectrum from T-2.72 to T+2.53 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.17. The fluence in the 15-150 keV band is 6.6 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.31 sec in the 15-150 keV band is 3.3 +- 0.4 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/536172/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13881 SUBJECT: GRB 121017A: GROND Observations DATE: 12/10/18 02:37:07 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann (MPE/Universe Cluster), M. Nardini (Milano-Bicocca), and J. Greiner (MPE) report on behalf of the GROND team: We observed the field of GRB 121017A (Swift trigger 536172, Grupe et al., GCN # 13875) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started on October 17, 2012, at 23:50 UT, 4.45 hr after the GRB trigger. They were performed at an average seeing of 1" (in r') and at an average airmass of 1.3. We do not detect any sources in the enhanced XRT error circle (Goad et al., GCN # 13879), in agreement with earlier reports of optical observations (Jelínek et al., GCN # 13876, Volnova et al., GCN # 13877, Gorosabel & Mottola, GCN # 13878). There is a star at the eastern edge of the error circle but this affects only a small part of it. Based on 284 s of total exposures in g'r'i'z' (mean time 0.18978 days after the trigger) and 480 s in JHK (mean time 0.19003 days after the trigger) we estimate preliminary AB magnitudes (upper limits are 3 sigma) of g' > 23.2, r' > 23.2, i' > 22.4, z' > 22.2, J > 19.8, H > 19.4 and K > 19.3. Given magnitudes are calibrated against GROND zeropoints in the optical as well as 2MASS field stars in the NIR and are not corrected for the high Galactic foreground reddening of E_(B-V) = 0.44 mag (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13882 SUBJECT: GRB 121017A: Swift-XRT refined Analysis DATE: 12/10/18 07:55:05 GMT FROM: Phil Evans at U of Leicester J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU) and D. Grupe report on behalf of the Swift-XRT team: We have analysed 8.0 ks of XRT data for GRB 121017A (Grupe et al. GCN Circ. 13875), from 1.1 ks to 30.0 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 13879). The light curve can be modelled with a power-law decay with a decay index of alpha=0.93 (+/-0.07). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.10 (+0.28, -0.27). The best-fitting absorption column is 6.0 (+1.7, -1.4) x 10^21 cm^-2, in excess of the Galactic value of 2.2 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 4.6 x 10^-11 (9.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.0 (+1.7, -1.4) x 10^21 cm^-2 Galactic foreground: 2.2 x 10^21 cm^-2 Excess significance: 4.4 sigma Photon index: 2.10 (+0.28, -0.27) If the light curve continues to decay with a power-law decay index of 0.93, the count rate at T+24 hours will be 9.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.4 x 10^-13 (8.7 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00536172. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13883 SUBJECT: GRB 121017A: Swift/UVOT Upper Limits DATE: 12/10/18 11:31:14 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL-UCL) and D. Grupe (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 121017A 1142 s after the BAT trigger (Grupe et al., GCN Circ. 13875). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 13879) 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 1142 1291 147 >21.1 white 1142 1442 167 >21.2 v 1298 1492 39 >18.5 b 1397 1417 19 >19.1 u 1373 1392 19 >18.6 w1 1347 1367 19 >18.1 w2 1448 1468 19 >18.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.44 in the direction of the burst (Schlegel et al. 1998).