TITLE: GCN CIRCULAR NUMBER: 24261 SUBJECT: GRB 190427A: Swift detection of a short burst DATE: 19/04/27 04:43:39 GMT FROM: David Palmer at LANL A. Tohuvavohu (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 04:34:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190427A (trigger=900730). Swift's slew will be delayed due to an observing constraint. The BAT on-board calculated location is RA, Dec 280.213, +40.322 which is RA(J2000) = 18h 40m 51s Dec(J2000) = +40d 19' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short structure with a duration of about 0.5 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+43.4 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is A. Tohuvavohu (aaronb AT swift.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/)