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)