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GCN Circular 8019

Subject
GRB 080725, Swift-BAT refined analysis
Date
2008-07-25T20:29:06Z (16 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
T. Ukwatta (GWU), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+130 sec from the recent telemetry 
downlink, we report further analysis of BAT GRB 080725 (trigger #317888)
(Krimm, et al., GCN Circ. 8014Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 121.699, -13.984 deg which is
   RA(J2000)  =  08h 06m 47.7s
   Dec(J2000) = -13d 59' 03.4"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 42%.

The mask-weighted light curve starts with a short, faint precursor from
T-105 to T-100 sec.  The main emission peak begins at T-20 sec and rises 
to a peak at T+2 sec.  There is a second peak at T+13 sec, and the 
emission falls to background levels by T+25 sec. T90 (15-350 keV) is 120 
(+5, -75) sec (estimated error including systematics).  The spacecraft 
slewed away from the burst location starting at T+100 sec, so there is 
no data beyond T+130 sec.

The time-averaged spectrum from T-105.5 to T+51.8 sec is best fit by a 
simple power-law model.  The power law index of the time-averaged 
spectrum is 1.50 +- 0.10.  The fluence in the 15-150 keV band is 3.7 +- 
0.2 x 10-6 erg/cm2. The 1-sec peak photon flux measured from T+3.54 sec 
in the 15-150 keV band is 2.3 +- 0.3 ph/cm2/sec.  All the quoted errors 
are at the 90% confidence level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/317888/BA/