GCN Circular 15296
M.C. Stroh and B. Sbarufatti report on behalf of the Swift-XRT team: We have analysed 1.8 ks of XRT data for GRB 131002B, from 58 s to 6.5 ks after the BAT trigger. The data comprise 282 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The light curve consists of a relatively flat region of WT data from T+58 to T+333 s with a count rate ranging between 10 and 50 cts/s. The WT observation ended when Swift entered the SAA. PC data exists from T+5.0 to T+6.5 ks with a count rates between 0.1 and 0.04 cts/s. Since there is only 1.8ks of data on this source, it is difficult to be confident that a fit to these data points truly models the overall behavior in this GRB. A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.46 (+0.04, -0.03). The best-fitting absorption column is consistent with the Galactic value of 9.1 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.7 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Galactic foreground: 9.1 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.46 (+0.04, -0.03) If the light curve continues to decay with a power-law decay index of 2.05, the count rate at T+24 hours will be 2.0 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.2 x 10^-15 (1.0 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00572742. This circular is an official product of the Swift-XRT team.