TITLE: GCN CIRCULAR NUMBER: 15944 SUBJECT: GRB 140311A: Swift detection of a probable burst DATE: 14/03/11 21:20:47 GMT FROM: David Palmer at LANL J. L. Racusin (NASA/GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (NASA/GSFC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (PSU), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 21:05:16 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140311A (trigger=591390). Swift could not immediately slew to the burst due to the Earth limb constraint. The BAT on-board calculated location is RA, Dec 209.301, +0.612 which is RA(J2000) = 13h 57m 12s Dec(J2000) = +00d 36' 41" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger and we cannot say much about the light curve. Due to an observing constraint, Swift will not slew until T0+50.6 minutes. There will be no XRT or UVOT data until this time. 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.)