TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3866 SUBJECT: GRB050824: Swift-BAT detection of a burst DATE: 05/08/25 00:31:30 GMT FROM: Scott Barthelmy at NASA/GSFC S. Campana (INAF-OAB), S. Barthelmy (GSFC), D. Burrows (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), S. Hunsberger (PSU), M. Ivanushkina (PSU), F. Marshall (GSFC), D. Palmer (LANL), G. Tagliaferri (INAF-OAB), on behalf of the Swift team: At 23:12:16 UT, Swift-BAT triggered and located GRB050824 (trigger=151905). This was a 64-sec image trigger. The spacecraft did not automatically slew due to proximity to the moon (25 degrees). Hence there will be no immediate results from XRT or UVOT. However, a TOO is being planned for this target. The BAT on-board calculated location is RA,Dec 12.237d,+22.592d {00h 48m 57s,+22d 35' 31"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows a broad peak from T+30 to T+70 sec. The emission is present only in the 15-50 keV band. The peak count rate was ~500 counts/sec (15-50 keV) at ~40 seconds after the trigger. At this early stage of the analysis we think this is likely a GRB, as there is no known gamma-ray source at this location in the SIMBAD database and the galactic latitude is -40 degrees.