TITLE:   GCN CIRCULAR
NUMBER:  7266
SUBJECT: GRB 080207: Swift-XRT Refined Analysis
DATE:    08/02/08 06:02:57 GMT
FROM:    Judith Racusin at PSU  <racusin@astro.psu.edu>

J. L. Racusin (PSU) reports on behalf of the Swift-XRT Team:

We have analysed the first 4 orbits of Swift-XRT data obtained for GRB
080207 (Racusin et al. GCN Circ. 7264), totaling 64 s of Windowed Timing
(WT) data and 5.7 ks of Photon Counting (PC) data.  The enhanced XRT
position is given in Beardmore et al. (GCN 7265).

The X-ray light-curve can be fit by a broken power-law with an initial
bright short flat phase with a a break at 205 +/- 73 sec followed by a
power-law with a decay slope of 1.5 +/- 0.1.

The WT data (133-197 seconds) can be modeled as an absorbed power-law with
photon index of 1.1 +/- 0.1 and a total absorbing column of NH = (85 +/-
10)e20 cm^-2.  The PC data (4.7-17.1 ks) can be modeled as an absorbed
power-law with photon index of 2.4 +/- 0.2 and a total absorbing column of
NH = (75 +/- 17)e20 cm^-2.  Both fits are in excess of the Galactic value
of 1.95e20 cm^-2. The 0.3-10 keV observed (unabsorbed) flux during this
time is 5.80e-9 (5.81e-9) erg cm^-2 s^-1 and 1.15e-11 (1.16e-11) erg cm^-2
s^-1 for WT and PC, respectively.

Assuming the source continues to decay with the same decay index of 1.5,
we predict an XRT count rate of 7.6e-3 counts/s at T+24 hours, which
corresponds to an 0.3-10.0 keV observed flux of 6.6e-13 ergs cm^-2 s^-1.

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