[vsnet-grb-info 7821] GRB 090515: Swift-BAT refined spectral analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9365
SUBJECT: GRB 090515: Swift-BAT refined spectral analysis
DATE:    09/05/15 15:29:10 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1 at 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.