TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3893 SUBJECT: GRB050827: Swift-BAT detection of a burst DATE: 05/08/27 19:26:32 GMT FROM: Scott Barthelmy at NASA/GSFC M. Capalbi (ASDC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), C. Markwardt (GSFC/UMD), D. Palmer (LANL), on behalf of the Swift-BAT team: At 18:57:15 UT, Swift-BAT triggered and located GRB050827 (trigger=152325). The spacecraft did not slew because of Moon constraint, and it will not be observable until ~13:00 UT 28/Aug/05 (T+18 hrs). The BAT on-board calculated location is RA,Dec 64.279d,+18.218d {04h 17m 07s,+18d 13' 03"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows multi-peaks with some pre-trigger emission starting at T-10 sec with a total duration of ~45 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~2 seconds after the trigger.