[vsnet-grb-info 6736] GRB 081007: Swift-XRT Team refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8336
SUBJECT: GRB 081007: Swift-XRT Team refined analysis
DATE:    08/10/07 18:37:29 GMT
FROM:    Kim Page at U.of Leicester  <kpa at star.le.ac.uk>

K.L. Page (U. Leicester) & W.H. Baumgartner (GSFC/UMBC) report on behalf 
of the Swift-XRT team:

We have analysed the XRT data obtained so far for GRB 081007 (Baumgartner 
et al., GCN Circ. 8330), consisting of 70 s of Windowed Timing (WT) mode 
and 8 ks of Photon Counting mode data. The UVOT-enhanced position was 
given by Beardmore et al. in GCN Circ. 8334

The X-ray light-curve showed an initial steep decay with alpha = 4.0 +/- 
0.2 until about 230 s after the burst, at which time the slope flattened 
to 0.74 +/- 0.05.

The WT spectrum can be fitted by a steep absorbed power-law, with Gamma = 
3.00 +0.27/-0.24 and NH = (6.6 +/- 1.1)e21 cm^-2 at z = 0.5295 (Berger, 
Fox & Cenko, GCN Circ. 8335), in addition to the Galactic value (at z=0) 
of 1.4e20 cm^-2. The observed (unabsorbed) flux over this time (105-176 s 
after the trigger) is 3.21e-10 (1.01e-9) erg cm^-2 s^-1.

If the decay continues at a slope of 0.74, the predicted count rate at 24 
hours after the burst is 0.019 count s^-1, corresponding to an observed 
(unabsorbed) flux of 7.6e-13 (1.2e-12) erg cm^-2 s^-1.

The results of the automatic analysis of the XRT data are available at 
http://www.swift.ac.uk/xrt_products

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