[vsnet-grb-info 4984] GRB 070802, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6699
SUBJECT: GRB 070802, Swift-BAT refined analysis
DATE:    07/08/02 15:04:30 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

J. Cummings (GSFC/UMBC), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
E. Fenimore (LANL), N. Gehrels (GSFC), S. Immler (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+776 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070802 (trigger #286809)
(Barthelmy, et al., GCN Circ. 6692).  The BAT ground-calculated position is
RA, Dec = 36.903, -55.517 deg, which is 
   RA(J2000)  =   2h 27m 36.7s 
   Dec(J2000) = -55d 31' 01" 
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.
 
The mask-weighted light curve for this 64-sec image trigger shows a single
peak starting at T+5 sec and ending at ~T+50 sec.  We note that there is
a 3-sigma blip at T-150 lasting about 20 sec.
T90 (15-350 keV) is 16.4 +- 1.0 sec (estimated error including systematics).
 
The time-averaged spectrum from T+4.9 to T+23.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.79 +- 0.27.  The fluence in the 15-150 keV band is 2.8 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+6.15 sec in the 15-150 keV band
is 0.4 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.