GCN Circular 7578
Subject
GRB 080409: Swift XRT refined analysis
Date
2008-04-09T11:53:54Z (17 years ago)
From
Rhaana Starling at U of Leicester <rlcs1@star.le.ac.uk>
R.L.C. Starling, P.A. Evans, K.L. Page (U. Leicester) and S.T. Holland
(CRESST/USRA/GSFC) report, on behalf of the Swift XRT team:
We have analysed the first three orbits of Swift XRT data (5.8 ks of data
from T0+96s to T0+1.29e4s) for GRB 080409 (Holland et al., GCN Circ.
7573). The enhanced position for the X-ray afterglow is given in Evans et
al. (GCN Circ. 7575).
The light curve shows an initial increase with slope of alpha1~0.6 up to
T~480s. The light curve then turns over to decay with a slope of
alpha2=-0.8+/-0.1.
The Photon Counting mode spectrum collected from the first three orbits
can be fit with an absorbed power law of photon index Gamma=2.2+0.5/-0.7
and a total absorbing column of NH=(5 +5/-4)e21 cm-2, exceeding the
Galactic value of 2.4e21 cm-2. The 0.3-10 keV observed (unabsorbed) flux
is 3.2e-12 (6.7e-12) erg/cm2/s, corresponding to a count rate of 5.8e-2
count/s and a count rate to flux conversion of 1 count/s = 5.6e-11 erg/cm2/s.
The predicted count rates at T0+24h and T0+48h are 6.8e-3 and 4.0e-3
count/s respectively, assuming the decay continues with alpha=-0.8.
This is an official product of the Swift XRT team.