TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3094
SUBJECT: Swift-BAT detection of GRB 050315
DATE:    05/03/15 21:55:41 GMT
FROM:    Ann M. Parsons at NASA/GSFC/Swift  <parsons@milkyway.gsfc.nasa.gov>

A. Parsons, S. Barthelmy, L. Barbier (GSFC), J. Cummings (GSFC/NRC),
E. Fenimore (LANL), R. Fink, N. Gehrels (GSFC), S. Holland (GSFC/USRA),
D. Hullinger (GSFC/UMD), K. Hurley (UCB), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), S. Piranomonte (ASDC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), A. Smale (NASA HQ), M. Suzuki 
(Saitama),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:

At 20:59:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB 050315.  The spacecraft automatically slewed
to the burst location, and UVOT began automated observations.  XRT was
not in a mode suitable for immediate position determination.

Using the time interval of the trigger of the burst, the 
ground-calculated
location is RA,Dec 306.476,-42.591 (J2000) with an uncertainty of 3 
arcmin
(radius, including a systematic uncertainty, 90% containment).
The burst was 40 degrees off the BAT boresight (60% coding).

The burst lightcurve has 2 overlapping FRED-like peaks.  The duration
is ~40 sec.  There is no further emmission out to T+180 sec, where the 
end
of the real-time TDRSS data ends.  The peak count rate is ~2500 
counts/sec.