TITLE: GCN CIRCULAR NUMBER: 22254 SUBJECT: Swift Trigger 797070 is probably not a GRB DATE: 17/12/14 04:40:56 GMT FROM: David Palmer at LANL E. Troja (NASA/GSFC/UMCP), A. Deich (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Swift Team: At 04:15:29 UT, the Swift Burst Alert Telescope (BAT) triggered and found a marginal significance image peak (trigger=797070). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 41.196, +15.317 which is RA(J2000) = 02h 44m 47s Dec(J2000) = +15d 19' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows count rate variations consistent with Swift J0243.6+6124, which is in the BAT field of view. The XRT began observing the field at 04:17:07.9 UT, 98.8 seconds after the BAT trigger. No source was detected in 684 s of promptly downlinked data. Due to the presence of a nearby bright star, UVOT finding charts are not available for this trigger. Swift followed up on this location, despite its low significance (6.78 sigma) because it is in the approximate direction of a nearby galaxy. However, the low significance, combined with the lack of an XRT counterpart, means that it is most likely to be a statistical fluctuation, rather than an astrophysical event. Final determination of the reality of the source will rely on the full downlinked dataset. Burst Advocate for this burst is E. Troja (eleonora.troja 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.)