TITLE: GCN CIRCULAR NUMBER: 19577 SUBJECT: GRB 160625A: Swift detection of a burst DATE: 16/06/25 22:56:43 GMT FROM: Scott Barthelmy at NASA/GSFC A. Maselli (INAF-IASFPA), S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 22:40:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160625A (trigger=701503). Swift did not slew to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 176.937, -65.114, which is RA(J2000) = 11h 47m 45s Dec(J2000) = -65d 06' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks in the first 40 sec and then a large peak at T+170 sec structure with a duration of at least 180 sec. The peak count rate was ~14000 counts/sec (15-350 keV), at ~175 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+20.3 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is A. Maselli (maselli AT ifc.inaf.it). 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.)