TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3044
SUBJECT: GRB 050219b: Swift-BAT detection of a burst
DATE:    05/02/20 01:03:47 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott@lheamail.gsfc.nasa.gov>

J. Cummings, S. Barthelmy, L. Barbier, J. Cannizzo (GSFC), M. Chester (PSU),
E. Fenimore, M. Galassi (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC), G. Sato (ISAS), M. Suzuki (Saitama),
T. Takahashi (ISAS), J. Tueller (GSFC), B. Zhang (UNLV)
on behalf of the Swift-BAT team:

At 21:05:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB050219b.  Because of the Earth-limb constraint,
the spacecraft could not immediately slew to the burst location.
The location became unconstrained at T+50 min, and the spacecraft slewed.
The XRT and UVOT instruments then began their standard set of pre-programmed
observing sequences.

Using the time interval of the burst, the ground-calculated location
is RA,Dec 81.287,-57.770 (J2000) with an uncertainty of 4 arcmin
(radius, including a systematic uncertainty, 90% containment).
The burst was 54 degrees off the BAT boresight (10% encoding).

The burst lightcurve has five overlapping peaks preceeded by a slow rise,
with a T90 duration of ~27 sec (and T50 is 6.8 sec).  The peak flux
is 26 ph/cm2/sec for a 1-sec interval (15-350 keV).  Using a simple power law
model, the fluence is ~2.3 (+/-30%) e-5 erg/cm^2 (15-350 keV).