TITLE: GCN CIRCULAR NUMBER: 6156 SUBJECT: GRB 070227: Swift detection of a burst in ground analysis DATE: 07/02/28 06:42:44 GMT FROM: Claudio Pagani at PSU/Swift-XRT C. Pagani (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU) and L. Vetere (PSU) report on behalf of the Swift Team: At 2007-02-27 22:21:59 Swift-BAT detected GRB 070227 (trigger 262347). The burst was not found automatically onboard, because a planned slew terminated the trigger prematurely. The burst was found later in ground analysis. Swift did not slew to the burst, and a target of opportunity observation for this burst will be uploaded at the next command opportunity (around 1400 UT). The BAT position is RA, Dec 120.566, -46.305 (J2000) RA: +08h 02m 16s Dec: -46d 18' 17" with an estimated error circle of 3 arcmin. The burst was in the extreme partially coded field of view, the coding was 3.4%. The burst as seen by BAT was a single peak at least 8 seconds long. We have detailed information for only T-2 to T+8 sec. Since the burst was weak and on the edge of the FOV, and because of the subsequent slew, we can not determine if additional emission occurred.