GCN Circular 8396
Subject
GRB 081016A: Swift-XRT refined analysis
Event
Date
2008-10-22T14:45:09Z (18 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT reobserved the field of the INTEGRAL GRB 081016A (Gotz et al.
GCN Circ. 8377) 5.2 days after the trigger, obtaining 3.8 ks of data in
Photon Counting (PC) mode. The source seen in the earlier XRT
observation (Evans, GCN Circ. 8379) was no longer detected. A
three-sigma upper limit on the count rate is 4.7e-3 counts/sec,
significantly below the level of the previous detection (0.03
counts/sec). We therefore confirm that this was the afterglow of
GRB 081016A.
A spectrum formed from the first XRT observation, totalling 2 ks in PC
mode, can be modelled with an absorbed power law with photon index
2.60 (+0.94, -0.81). The absorption column is consistent with the
Galactic value of 1.7e21 cm^-2 (Kalberla et al 2005). The counts to
observed (unabsorbed) flux conversion factor is 1.1e-12 (3.0e-12) erg
cm^-2 ct^-1.
This circular is an official product of the Swift-XRT team.