[vsnet-grb-info 1898] GRB 050802: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3737
SUBJECT: GRB 050802: Swift-BAT refined analysis
DATE:    05/08/02 15:16:08 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori at milkyway.gsfc.nasa.gov>

D. Palmer (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC), 
P. Boyd (GSFC-UMBC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), 
N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), 
C. Markwardt (GSFC/UMD), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), 
G. Sato (ISAS), J. Tueller (GSFC), W. Voges (MPE), 
on behalf of the Swift-BAT team:

At 10:08:02 UT Swift-BAT detected GRB 050802 (trigger=148646)
(GCN Circ 3734, Band, et al.).  The refined BAT ground position
is (RA,Dec) = 219.287, +27.806 {14h37m08.9s, 27d48'21.6"} [deg; J2000]
+-3 arcmin, (95% containment).  The partial coding was 27%.  

The light curve has a 5 second rise time to the first and largest
of 3 symmetrical peaks in the interval T-5 to T+13 seconds. There
is a hint of a small peak at T+30 seconds. T90 (15-350 keV) is
(13 +- 2) seconds (estimated error including systematics). 

The power law index of the time-averaged spectrum is 1.6 +- 0.1.  
The fluence in the 15-350 keV band is (2.8 +- 0.3) x 10^-6 erg/cm2.  
The 1-s peak photon flux measured from T0-0.4 second in the 15-350 keV 
band is (3.3 +- 0.5) ph/cm2/s.  All the quoted errors are at the 90% 
confidence level. 

There was no BAT Position GCN Notice on this burst, because none was 
transmitted from the spacecraft.  The cause is being investigated.