//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12667 SUBJECT: GRB 111212A: Swift detection of a burst DATE: 11/12/12 09:41:19 GMT FROM: David Palmer at LANL S. Campana (INAF-OAB), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), P. A. Evans (U Leicester), B. Gendre (ASDC), C. Guidorzi (U Ferrara), O. M. Littlejohns (U Leicester), A. Melandri (INAF-OAB), P. T. O'Brien (U Leicester), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), C. A. Swenson (PSU), E. Troja (NASA/GSFC/ORAU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 09:23:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 111212A (trigger=509543). Swift could not slew immediately to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 310.404, -68.617 which is RA(J2000) = 20h 41m 37s Dec(J2000) = -68d 37' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a weak emission with a duration of at least 20 sec, but a more detailed description will require the ground-linked data. The peak count rate was ~500 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+47.6 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is C. A. Swenson (cswenson 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: 12669 SUBJECT: GRB 111212A: Swift-XRT observations DATE: 11/12/12 11:24:01 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), G. Tagliaferri (INAF-OAB), S. Campana (INAF-OAB), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows (PSU) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 111212A at 10:17:35.0 UT, 3267.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 310.43423, -68.61205 which is equivalent to: RA(J2000) = 20h 41m 44.22s Dec(J2000) = -68d 36' 43.4" with an uncertainty of 3.5 arcseconds (radius, 90% containment). This location is 43 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 (3.07 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2 (+0.94/-0.88) x 10^21 cm^-2 (90% confidence). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12670 SUBJECT: GRB 111212A: Enhanced Swift-XRT position DATE: 11/12/12 14:11:53 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 2469 s of XRT Photon Counting mode data and 7 UVOT images for GRB 111212A, 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 = 310.43132, -68.61251 which is equivalent to: RA (J2000): 20h 41m 43.52s Dec (J2000): -68d 36' 45.0" with an uncertainty of 1.5 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: 12671 SUBJECT: GRB 111212A: Swift-BAT refined analysis DATE: 11/12/12 14:55:22 GMT FROM: Scott Barthelmy at NASA/GSFC T. N. Ukwatta (MSU) S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 111212A (trigger #509543) (Campana, et al., GCN Circ. 12667). The BAT ground-calculated position is RA, Dec = 310.442, -68.585 deg, which is RA(J2000) = 20h 41m 46.0s Dec(J2000) = -68d 35' 04.5" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a FRED-like pulse starting at ~T-2 sec, peaking at ~T+6 sec, and returning to background around T+60 sec. Since Swift slewed due to an observing constraint, the burst location left the BAT FoV at ~T+70 sec, so we can not say if there was further actitivty in the lightcurve. The time-averaged spectrum from T-5.77 to T+62.74 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.67 +- 0.18. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+4.76 sec in the 15-150 keV band is 0.8 +- 0.3 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/509543/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12672 SUBJECT: GRB 111212A: Swift/UVOT Upper Limits DATE: 11/12/12 15:55:48 GMT FROM: Craig Swenson at PSU/Swift C. A. Swenson (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 111212A 3272 s after the BAT trigger (Campana et al., GCN Circ. 12667). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 12670) 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 3272 3422 147 >20.3 white 3272 5481 541 >21.3 v 4255 5751 255 >19.2 b 3637 5276 393 >20.1 u 3432 5071 393 >20.1 w1 4665 4865 197 >20.1 m2 4460 4660 197 >20.3 w2 4050 5687 393 >21.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12674 SUBJECT: GRB 111212A: Swift-XRT refined Analysis DATE: 11/12/12 22:19:20 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU) reports on behalf of the Swift-XRT team: We have analysed 6.5 ks of XRT data for GRB 111212A (Campana et al. GCN Circ. 12667), from 3.3 ks to 17.3 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 12670). The light curve can be modelled with a power-law decay with a decay index of alpha=1.39 (+0.11, -0.10). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.05 (+0.13, -0.07). The best-fitting absorption column is 9.5 (+3.0, -1.6) x 10^20 cm^-2, in excess of the Galactic value of 3.1 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 3.5 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 9.5 (+3.0, -1.6) x 10^20 cm^-2 Galactic foreground: 3.1 x 10^20 cm^-2 Excess significance: 6.6 sigma Photon index: 2.05 (+0.13, -0.07) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00509543. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12679 SUBJECT: GRB 111212A: GROND observations DATE: 11/12/14 09:11:29 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann, A. Rossi (TLS Tautenburg), V. Sudilovsky, P. Schady and J. Greiner, (MPE Garching) report on behalf of the GROND team: We observed the field of the Swift GRB 111212A (Swift trigger 509543; Campana et al., GCN #12667) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP, 120, 405) mounted at the 2.2 m ESO/MPG telescope at La Silla Observatory (Chile). Observations started on December 13, 2011, at 00:35 UT, in twilight, and are centered 0.658 days after the GRB trigger. They were taken at an average seeing of 1".2 and at an airmass of 2. Integration times were 1734 sec in the optical and 2640 sec in the NIR. These observations were obtained under challenging conditions, with thick cirrus preventing guiding. A second epoch was obtained on December 14, 2011, starting at 00:57 UT and centered at 1.667 days after the GRB. It was taken at an average seeing of 1".2 and at an airmass of 2. Integration times were 2420 sec in the optical and 2160 sec in the NIR. Conditions were much better, with clear, moonless skies. At the position of the X-ray afterglow (Osborne et al., GCN #12670), we do not detect any significant sources in any bands. We derive the following limits (3 sigma, AB magnitude system): 0.658 days after the trigger: g' > 24.1 r' > 24.2 i' > 23.4 z' > 22.8 J > 20.5 H > 20.0 K > 18.1 1.667 days after the trigger: g' > 24.8 r' > 24.8 i' > 23.8 z' > 23.4 J > 21.6 H > 21.0 K > 19.3 Magnitudes were calibrated against GROND zero points in g'r'i'z' and 2MASS field stars in JHK.