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GCN Circular 9365

GRB 090515: Swift-BAT refined spectral analysis
2009-05-15T15:29:10Z (15 years ago)
Takanori Sakamoto at NASA/GSFC <>
T. Sakamoto (GSFC/UMBC), A. P. Beardmore (U Leicester) 
on behalf of the Swift-BAT team

Based on a further analysis of the BAT spectrum of GRB 090515 
(Barthelmy, et al. , GCN Circ. 9364), we found that the spectrum shows 
a significant improvement of chi2 by a power-law with an exponential 
cutoff (chi squared 52.55 for 56 d.o.f.) over a simple power-law 
(chi squared 58.63 for 57 d.o.f.).  This fit gives a photon index 
-0.05 +- 1.36, and Epeak of 64 +- 23 keV.  For this model 
the total fluence in the 15-150 keV band is 2.0 +- 0.3 x 10^-8 erg/cm2.  
All the quoted errors are at the 90% confidence level.
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