GCN Circular 9365
Subject
GRB 090515: Swift-BAT refined spectral analysis
Date
2009-05-15T15:29:10Z (16 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori.sakamoto-1@nasa.gov>
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.