TITLE: GCN CIRCULAR NUMBER: 7746 SUBJECT: GRB 080517: Swift-XRT refined analysis DATE: 08/05/18 07:39:17 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) and A.M. Parsons (GSFC) report on behalf of the Swift-XRT team: We have analysed the first two snapshots of Swift-XRT data obtained for GRB 080517 (Parsons et al, GCN Circ. 7742), comprising 3.3 ks in Photon Counting (PC) mode, starting 144 s after the BAT trigger. The UVOT-enhanced XRT position was given in Evans et al. (GCN Circ. 7744) The light curve can be described as a broken power-law, with an initial decay of 2.47 (+0.25/-0.23), with a break at T+~1100s to a slope of 0.57 (+0.25/-0.74). A spectrum obtained from all of the PC data can be modelled with an absorbed power-law, with gamma=1.91 (+0.36/-0.34) and an absorption column of 1.41 (+0.10/1.11) e21 cm^-2, in excess of the Galactic value of 8.12e20 cm^-2 (Kalberla et al. 2005). The observed (unabsorbed) flux in this spectrum is 6.07 (8.12) e-12 erg cm^-2 s^-1. The counts to observed flux conversion is 5.93e-11 erg cm^-2 count^-1. If the light-curve continues to decay at alpha=0.57 the count rate at 24 hours is predicted to be 1.6e-3 count s-1, corresponding to an observed (unabsorbed) flux of 7.10 (9.49) e-14 erg cm^-2 s^-1. This is an official product of the Swift-XRT team.