[vsnet-grb-info 2254] GRB 051012: Swift-BAT detection of burst yesterday

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4093
SUBJECT: GRB 051012: Swift-BAT detection of burst yesterday
DATE:    05/10/13 22:15:40 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc at milkyway.gsfc.nasa.gov>

G. Sato (ISAS), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/NRC), N. Gehrels (GSFC), D. Hinshaw (GSFC-SPSYS),
H. Krimm (GSFC/USRA), K. McLean (LANL), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC), J. Tueller (GSFC),
on behalf of the Swift-BAT team:


At 2005-10-12 17:05:58 UT, Swift-BAT triggered and detected GRB 051012
(trigger 159413).  Because Swift was executing a preplanned slew, the 
burst was not identified onboard and no prompt notices were distributed.
Using the data set from T-4 to T+16, the refined BAT ground position is 
RA, Dec 270.564d, -52.795d {18h 02m 15s, -52d 47' 40"} [deg; J2000], 
+- 1.8 arcmin (radius, sys+stat, 90% containment). The burst was in the
fully-coded field of view.

The lightcurve shows a single weak peak with a slow rise and fall from
approximately T-3 to T+11 sec.  T90 (15-350 keV) was 13 +- 1 sec (estimated 
error including systematics).  Because of the slew, we cannot rule out 
further emission after T+16 sec.

The power law index of the time-averaged spectrum was 2.25 +- 0.25.  The
fluence in the 15-150 keV band was (2.9 +- 0.5) x 10^-7 ergs / cm^2.  The
1-sec peak flux measured from T+3 sec in the 15-150 keV band was
0.6 +- 0.2 photons / cm^2 sec. All the quoted errors are at the 90%
confidence level.