TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4069 SUBJECT: GRB051008: Swift-BAT detection of a bright burst DATE: 05/10/08 17:13:00 GMT FROM: Scott Barthelmy at NASA/GSFC F. Marshall (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), J. Norris (GSFC), M. Perri (ASDC), T. Sakamoto (GSFC) on behalf of the Swift team: At 16:33:21 UT, Swift-BAT triggered and located GRB051008 (trigger=158855). The spacecraft did not slew immediately because of the Earth observing constraint. The burst will be observed by the NFIs at T+48 minutes when it comes out of constraint. The BAT on-board calculated location is RA,Dec 202.870d,+42.090d {13h 31m 29s,+42d 05' 26"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows two main overlapping peaks with a total duration of ~30 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~4 seconds after the trigger. This burst happened during a Malindi telemetry down link session, so the TDRSS burst-related notices were delayed in transmission until the end of the downlink pass (~10 min).