TITLE: GCN CIRCULAR NUMBER: 13763 SUBJECT: GRB 120913B: Swift detection of a burst DATE: 12/09/14 00:04:22 GMT FROM: Scott Barthelmy at NASA/GSFC E. A. Helder (PSU), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), D. Grupe (PSU), S. T. Holland (STScI), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 23:55:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120913B (trigger=533613). Swift did not slew because of the Sun observing constraint. The BAT on-board calculated location is RA, Dec 213.644, -14.535 which is RA(J2000) = 14h 14m 35s Dec(J2000) = -14d 32' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks with a total duration of about 70 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~5 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 20:57 UT on 2012 December 14. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is E. A. Helder (helder 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.)