//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12310 SUBJECT: GRB 110827A: Swift detection of a burst DATE: 11/08/27 00:11:29 GMT FROM: David Palmer at LANL B.-B. Zhang (PSU), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), D. Grupe (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 00:01:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110827A (trigger=501520). Swift could not slew to this burst due to the Sun constraint. The BAT on-board calculated location is RA, Dec 164.095, +53.787 which is RA(J2000) = 10h 56m 23s Dec(J2000) = +53d 47' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 30 sec. The peak count rate was ~600 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 2011 September 05. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is B.-B. Zhang (bbzhang AT 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: 12312 SUBJECT: GRB 110827A, Swift-BAT refined analysis DATE: 11/08/27 13:54:44 GMT FROM: Hans Krimm at NASA-GSFC T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), 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), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU), B.-B. Zhang (PSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 110827A (trigger #501520) (Zhang, et al., GCN Circ. 12310). The BAT ground-calculated position is RA, Dec = 164.059, 53.817 deg which is RA(J2000) = 10h 56m 14.2s Dec(J2000) = +53d 49' 01.2" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single peak starting at ~T-15 sec, peaking at T+5 sec and returning to background by T+35 sec. At T+195 sec, a pre-planned slew moved the source out of the field of view. T90 (15-350 keV) is 8.5 +- 1.1 sec (estimated error including systematics). The time-averaged spectrum from T-2.9 to T+6.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.24 +- 0.27. The fluence in the 15-150 keV band is 1.8 +- 0.3 x 10-07 erg/cm2. The 1-sec peak photon flux measured from T+2.12 sec in the 15-150 keV band is 0.4 +- 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/501520/BA/