TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3038 SUBJECT: GRB 050219: Swift-BAT detection of a burst DATE: 05/02/19 18:23:22 GMT FROM: Scott Barthelmy at NASA/GSFC D. Hullinger (GSFC/UMD), S. Barthelmy, L. Barbier, J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), J. Norris (GSFC), J. Nousek (PSU), D. Palmer (LANL), A. Parsons (GSFC), M. Perri (ASDC), T. Sakamoto (GSFC), G. Sato (ISAS), A. Smale (NASA HQ), M. Suzuki (Saitama), J. Tueller (GSFC), B. Zhang (UNLV) on behalf of the Swift-BAT team: At 12:40:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located on-board GRB050219. The spacecraft autonomously slewed to the burst location (started at T+12 sec and was on target at T+78 sec). The XRT and UVOT instruments then began their standard set of pre-programmed observing sequences. Using the time interval of the burst before the slew, the ground-calculated location is RA,Dec 166.409,-40.677 (J2000) with an uncertainty of 4 arcmin (radius, including a systematic uncertainty, 90% containment). The burst was 43 degrees off the BAT boresight (30% encoding). It is within 25 arcsec of the XRT position (Romano et al., GCN Circ 3036). The burst lightcurve has two overlapping peaks, with a T90 duration of ~23 sec. The peak flux is 5.5 ph/cm2/sec for a 1-sec interval (15-350 keV). The fluence is ~9.4e-6 erg/cm^2 (15-350 keV).