TITLE: GCN CIRCULAR NUMBER: 7859 SUBJECT: GRB 080607: Swift-XRT refined analysis DATE: 08/06/07 22:46:45 GMT FROM: Boris Sbarufatti at INAF-IASF-Pa B. Sbarufatti, V. Mangano, V. La Parola (INAF-IASF Pa) report on behalf of the Swift-XRT team. Swift-XRT began observations of the field of GRB 080607 (trigger 313417, Mangano et al., GCN circ. 7847) on date 2008 June 07, 06:08:54 UT, 87 s after the BAT trigger. The data consist of 478 s in Windowed timing mode and 3 ks in Photon Counting mode. The lightcurve shows a complex behaviour. After an initial steep decay (index 5.8 +/- 0.4) we observe a double peaked flare, starting at T+ 118 (+/- 1) s and peaking at T+120 s and T+140 s. The underlying decay breaks at T+ 119 (+ 5, - 2) s to a slope of 1.7 (+/- 0.1). A second break at t+700 (+/- 300) marks the beginning of a plateau phase (index 0.5 +/- 1.3). The lightcurve breaks again around T+1600 (+/- 500) s, with a final decay index of -2.0 +/- 0.5. The countrate predictions for T+24h and T+48h are 2.1E-3 counts/s and 5.5E-4 count/s respectively. The WT spectrum can be fit by a powerlaw with photon index 1.81 +/- 0.02 and an intrinsic absorbing column density of (4.0 +/- 0.2)E22 cm^-2 at z=3.036 (Prochaska et al. GCN Circ. 7849), in excess with respect to the Galactic value of 1.69E+20 cm^-2 (Kalberla et al. 2005). The observed (unabsorbed) flux in the 0.3 - 10 keV band is 2.9 (3.0)E-9 erg cm^-2 s^-1. The PC spectrum can be fit by a powerlaw with photon index 2.1 +/- 0.1 and an intrinsic absorbing column density of (4.0 +/- 0.8)E22 cm^-2 at z=3.036, in excess with respect to the Galactic value. The observed (unabsorbed) flux in the 0.3 - 10 keV band is 5.3 (5.4)E-11 erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. [GCN OPS NOTE(08jun08): Per author's request, the "(4.0 +/- 0.8)E21" was changed to "(4.0 +/- 0.8)E22".]