TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5240 SUBJECT: GRB 060607: Swift-XRT Team refined analysis DATE: 06/06/07 13:10:12 GMT FROM: Kim Page at U.of Leicester Kim Page, Mike Goad & Andy Beardmore (U. Leicester) report on behalf of the Swift-XRT team: We have analysed the first 3 orbits of X-ray data obtained for GRB 060607 (BAT trigger 213823; Ziaeepour et al., GCN 5233). The data show 3 flares, superimposed on a decay of alpha_1 = 1.09 +/- 0.04. Around 740 seconds after the trigger, the slope flattens, becoming alpha_2 = 0.45 +/- 0.03. The flares in the WT data show spectral evolution. The later PC data are well-fitted by a single power-law with Gamma = 1.64 +/- 0.07, with excess NH above the Galactic value. Taking the redshift to be 3.082 (Ledoux et al; GCN 5237), the intrinsic NH is (7.9 +3.8/-3.5)e21 cm^-2. Assuming the shallow decay of alpha_2 = 0.37 continues, the count rate is estimated to be 0.49 count s^-1 at 24 hours. This corresponds to an observed (unabsorbed) flux of 2.22e-11 (2.44e-11) erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team.