GCN Circular 10125
Subject
GRB 091102: Swift-XRT refined analysis
Event
Date
2009-11-03T06:23:30Z (16 years ago)
From
Loredana Vetere at PSU <vetere@astro.psu.edu>
L. Vetere and E. A. Hoversten (PSU) report on behalf of the Swift-XRT
team:
We have analysed 1.4 ks of XRT data for GRB 091102 (Hoversten et al.
GCN Circ.
10117), from 988 s to 19 ks after the BAT trigger. The data are
entirely in
Photon Counting (PC) mode. The enhanced XRT position has already been
determined
by Kennea et al. (GCN Circ. 10120).
The PC light curve shows a steep drop at 1.3 ks after the BAT trigger
with a
decay index of alpha=2.9 +/- 0.6.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law
with a photon spectral index of 2.0 (+0.8, -0.6). The best-fitting
absorption
column is 2.4 (+2.5, -1.3) x 10^21 cm^-2, consistent with the Galactic
value of
1.1 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed
(unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is 4.2 x
10^-11
(6.3 x 10^-11) erg cm^-2 count^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00374598.
This circular is an official product of the Swift-XRT team.