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GCN Circular 13581

Subject
GRB 120804A: Swift-BAT refined analysis
Date
2012-08-04T13:20:44Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120804A (trigger #529686)
(Lien, et al., GCN Circ. 13573).  The BAT ground-calculated position is
RA, Dec = 233.951, -28.768 deg, which is 
   RA(J2000)  =  15h 35m 48.1s 
   Dec(J2000) = -28d 46' 06.1" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 24%.
 
The mask-weighted light curve shows two overlapping peaks starting
at ~T-0.2 sec, peaking at ~T+0.1 and ~T+0.5 sec, and ending at ~T+1.0 sec.
T90 (15-350 keV) is 0.81 +- 0.08 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.16 to T+0.83 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.34 +- 0.08.  The fluence in the 15-150 keV band is 8.8 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.16 sec in the 15-150 keV band
is 10.8 +- 0.6 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/529686/BA/
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