TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3237 SUBJECT: Swift-BAT Detection of GRB 050412: A Bright, Long Burst DATE: 05/04/12 07:21:04 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. Cummings (GSFC/NRC), L. Barbier, S. Barthelmy (GSFC), E. Fenimore (LANL), M. Galassi (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), M. Tripicco (GSFC-SSAI), J. Tueller (GSFC), D. Burrows (PSU), J. Kennea (PSU), V. Mangano (IASF-CNR) on behalf of the Swift team: At 05:44:03 UT, Swift-BAT triggered on burst GRB 050412 (trigger=114485) and began to slew 35 seconds after the trigger. The BAT onboard position is RA, Dec = 181.120, -1.252 (J2000) with an estimated error of <4 arcminutes. The lightcurve shows a complex multi-peaked emission from 9 seconds before the trigger to at least 15 seconds after. There was strong flux in all energy bands from 15 to 350 keV. The 1 second peak count rate is 0.8 ph/cm2/s (15-350 keV). We note that this burst is well suited for ground-based followup, being anti-Sunward, far from the Moon, away from the Galactic plane, and equatorial. No object was detected by the XRT on-board software, beginning at about T+100 seconds. However, the XRT counting rate is slightly elevated, indicating a possible weak counterpart. Further information from all 3 Swift instruments will be available when data from the Malindi ground station are received and processed at about 11:00 UT.