TITLE: GCN CIRCULAR NUMBER: 19458 SUBJECT: GRB 160525A: Swift detection of a probable burst DATE: 16/05/25 01:47:52 GMT FROM: David Palmer at LANL M. Stamatikos (OSU/NASA/GSFC), A. D'Ai (INAF-IASFPA), C. Gronwall (PSU), A. Maselli (INAF-IASFPA) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 01:33:59 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160525A (trigger=687492). Swift could not slew to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 103.530, -0.173 which is RA(J2000) = 06h 54m 07s Dec(J2000) = -00d 10' 24" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, there is no obvious variation in the immediately available lightcurve. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 12:15 UT on 2016 August 19. There will thus be no XRT or UVOT data for this trigger before this time. Although the observing constraint prevents a confirmation of this untriggered event, its significance (7.2 sigma) makes it most likely to be a real astrophysical event. A more definite determination will require the full downlinked dataset. Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 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.)