TITLE: GCN CIRCULAR NUMBER: 24027 SUBJECT: GRB 190331A: Swift detection of a burst DATE: 19/03/31 02:42:45 GMT FROM: David Palmer at LANL K. L. Page (U Leicester), S. D. Barthelmy (GSFC), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 02:14:37.50 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190331A (trigger=895813). Swift did not slew immediately due to an observing constraint. The BAT on-board calculated location is RA, Dec 28.576, +27.619 which is RA(J2000) = 01h 54m 18s Dec(J2000) = +27d 37' 10" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a bright multi-peaked structure with a duration of about 5 sec. The peak count rate was ~6000 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 18:15 UT on 2019 June 12. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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/)