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GCN Circular 3793

GRB 050813: Swift-BAT refined analysis
2005-08-13T19:01:47Z (19 years ago)
Craig Markwardt at NASA/GSFC/UMD <>
G. Sato (ISAS), L. Angelini (GSFC-JHU), L. Barbier (GSFC), 
S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), 
N. Gehrels (GSFC), J. Grenier (MPE), D. Hullinger (UMD), 
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), T. Mitani (ISAS), 
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), 
G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), 
on behalf of the Swift/BAT team:

At 06:45:09.76 UT Swift-BAT detected GRB 050813 (trigger=150139) (GCN
Circ 3788, Retter et al.).  The refined BAT ground position is
(RA,Dec) = 241.988, +11.246, [deg; J2000] +- 3 arcmin, (95%
containment radius).  The partial coding was 57%.  This is 7 arcsec from the
XRT position (Morris et al., GCN 3790).

The burst has a short spike lasting ~32 msec, overlayed on broader
peak of duration ~0.6 sec.  There is a hint of a second peak at T+1.3
seconds.  T90 (15-350 keV) is (0.6 +- .1) seconds (estimated error
including systematics).

The photon index of the time-averaged spectrum is 1.19 +- 0.33.  
The fluence in the 15-350 keV band is (1.24 +- 0.46) x 10^-7 erg/cm2.  
The 1-s peak photon flux measured from T+0.1 second in the 15-350 
band is (1.22 +- 0.26) ph/cm2/s.  All the quoted errors are at the 90% 
confidence level.
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