[AAVSO-HEN] GRB 080802: Swift-XRT Refined Analysis

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  8054
SUBJECT: GRB 080802: Swift-XRT Refined Analysis
DATE:    08/08/03 03:20:34 GMT
FROM:    Michael Stroh at PSU/Swift  <stroh at astroh.org>

M.C. Stroh (PSU) reports on behalf of the Swift-XRT team:

We have analyzed the first two orbits of Swift-XRT data obtained for  
GRB 080802 (Baumgartner et al., GCN Circ. 8051), totaling 81s of  
Windowed Timing and 2.4ks of Photon Counting data.

The X-ray light-curve begins with a single flare that peaks to ~40 cts/ 
s near T+100 seconds. The rest of the light-curve can be fit by a  
single broken power-law with an initial decay index of 2.91 +/- 0.33,  
second decay index of -0.51 +/- 0.25 and a break near T+1000s. Since  
the second decay index indicates brightening, we cannot accurately  
predict counting rates at T+24 or T+48 hours.

The spectrum from the Windowed Timing data can be fit with a power-law  
in excess of the Galactic value (2.75e21 cm-2, Kalberla et al. 2005),  
with a column density of 4.8 (+2.0/-1.7)e21 cm^-2 and a photon index  
of 1.40 (+0.24/-0.22). The observed (unabsorbed) 0.3-10 keV flux is  
4.78e-10 (4.95e-10) ergs/cm^2/s.

This is an official product of the Swift-XRT team.