TITLE: GCN CIRCULAR NUMBER: 16808 SUBJECT: GRB 140909A: Swift detection of a GRB DATE: 14/09/09 17:59:24 GMT FROM: David Palmer at LANL David Palmer reports on behalf of the Swift Team: In two successive 64-second images, beginning at 06:56:51, BAT detected a source at a consistent location. Although the individual images were below threshold, the combined detection is highly significant, in excess of 8 sigma. A 320 s image that includes the data from both 64 s images indicates additional flux outside of the 128 s time interval. The BAT on-board calculated location is RA,dec = 193.638,63.494 (J2000), which is RA(J2000) = 12h 54m 33s Dec(J2000) = +63d 29� 38� As is usual for image triggers, there is no obvious variation in the BAT lightcurve. Because the individual images were below threshold, Swift did not automatically slew to the location. However, a ToO has been requested. -- David Palmer palmer@lanl.gov (505)665-6863 (voice) (505)665-4414 (fax)