[vsnet-grb-info 6801] GRB 081016A: Swift-XRT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8396
SUBJECT: GRB 081016A: Swift-XRT refined analysis
DATE:    08/10/22 14:45:09 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at 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.