//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11310 SUBJECT: GRB 100928A: Swift detection of a burst DATE: 10/09/28 02:34:10 GMT FROM: Valerio D'Elia at ASDC V. D'Elia (ASDC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), G. Stratta (ASDC) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team: At 02:19:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 100928A (trigger=435160). The BAT on-board calculated location is RA, Dec 223.036, -28.561 which is RA(J2000) = 14h 52m 09s Dec(J2000) = -28d 33' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 6 sec. The peak count rate was ~700 counts/sec (15-350 keV), at ~1 sec after the trigger. There may be additional emission at T+180 sec. Due to an Sun observing constraint, Swift cannot slew to the BAT position until 20:05 UT on 2010 December 26. There will thus be no XRT or UVOT data for this trigger. 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: 11312 SUBJECT: GRB 100928A, Swift-BAT refined analysis DATE: 10/09/28 12:40:44 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), E. E. Fenimore (LANL), N. Gehrels (GSFC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (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 100928A (trigger #435160) (D'Elia, et al., GCN Circ. 11310). The BAT ground-calculated position is RA, Dec = 223.037, -28.542 deg which is RA(J2000) = 14h 52m 09.0s Dec(J2000) = -28d 32' 32.5" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 15%. The mask-weighted light curve showed a single peak starting at T-1 with a total duration of ~6 seconds. T90 (15-350 keV) is 3.3 +- 0.6 sec (estimated error including systematics). The time-averaged spectrum from T+0.9 to T+4.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.79 +- 0.29. The fluence in the 15-150 keV band is 3.5 +- 0.6 x 10-7 erg/cm2. The 1-sec peak photon flux measured from T+1.31 sec in the 15-150 keV band is 2.5 +- 0.5 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/435160/BA/