TITLE:   GCN CIRCULAR
NUMBER:  7754
SUBJECT: GRB 080520: Swift XRT Refined Analysis
DATE:    08/05/21 04:32:15 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

Dirk Grupe reports on behalf of the Swift-XRT team:


The XRT began observing the field of GRB 080520 (trigger=312047; Grupe 
et al.,
GCN Circ 7753) on 2008-May-20 at 22:22:04.3 UT, 99.5 seconds after
the BAT trigger.


The 0.3-10 keV X-ray light curve of the first two orbits
displays a single decay with a slope alpha=1.04+/-0.07.  

The spectrum of the Photon Counting data of the first two orbits
can be well fitted by an absorbed single powerlaw model with a photon
index Gamma = 2.12 +/- 0.20 and a column density consistent with the 
Galactic
value of 6.48e20 cm-2

If the underlying powerlaw decay continues as is, we predict an XRT 
count rate
of 1e-3 counts/s at T+24 hours or 5e-14 ergs/s/cm2 and at T+48 hours 4e-4
counts/s or 2e-14 ergs/s/cm2.

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