TITLE: GCN CIRCULAR NUMBER: 13191 SUBJECT: GRB 120403A: Swift detection of a burst DATE: 12/04/03 01:25:54 GMT FROM: Scott Barthelmy at NASA/GSFC A. P. Beardmore (U Leicester), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 01:05:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120403A (trigger=519211). Swift did not slew because of the Sun observering constraint. The BAT on-board calculated location is RA, Dec 42.459, +40.466 which is RA(J2000) = 02h 49m 50s Dec(J2000) = +40d 27' 57" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 2 sec. The peak count rate was ~2200 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 18:44 UT on 2012 June 25. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 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.)