GCN Circular 8396
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.