GCN Circular 3111

H. Krimm (GSFC/USRA), S. Barthelmy, L. Barbier (GSFC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (GSFC/UMD), C. Markwardt (GSFC/UMD), T. McMahon (Langston U.),
P. Meszaros (PSU), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Still (GSFC/USRA),
M. Suzuki (Saitama), M. Tripicco (GSFC-SSAI) J. Tueller (GSFC)
on behalf of the Swift-BAT team:

At 15:44:37 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB 050318.  The spacecraft did not automatically slew
to the burst location because of an observing constraint.  The orbit is such
that we just started the approximate 6-hour gap in telemetry downlink orbits,
so it will be ~7 hours before we get the full data set on this burst
and can say anything more than what is available from the real-time
TDRSS messages.

Using the time interval of the trigger of the burst (0.5 sec),
the ground-calculated location is RA,Dec 49.651,-46.392 (J2000)
with an uncertainty of 3 arcmin (radius, including a systematic uncertainty,
90% containment).  The burst was 22 degrees off the BAT boresight (75% coding).

The burst lightcurve has 2 peaks.  The first peak is ~3 sec long with a peak
count rate of 4000 cnts/sec.  The second peak starts at T+25 and lasts ~15 sec
with a peak rate of 4500 cnts/sec (15-350 keV) .