TITLE: GCN CIRCULAR NUMBER: 15945 SUBJECT: GRB 140311B: Swift detection of a burst DATE: 14/03/11 21:36:02 GMT FROM: Judith Racusin at GSFC J. L. Racusin (NASA/GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (NASA/GSFC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 21:14:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140311B (trigger=591392). Swift could not immediately slew to the burst due to the Earth limb constraint. The BAT on-board calculated location is RA, Dec 252.291, +52.747 which is RA(J2000) = 16h 49m 10s Dec(J2000) = +52d 44' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). We are awaiting information on the BAT light curve. Due to an observing constraint, Swift will not slew until T0+55 minutes. There will be no XRT or UVOT data until this time. The observation of this burst will delay the observation of GRB 140311A. Burst Advocate for this burst is J. L. Racusin (judith.racusin AT nasa.gov). 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.)