GCN Circular 10320
L. Vetere (PSU) reports on behalf of the Swift-XRT team: We have analysed 774 s of XRT data for GRB 100111A (Vetere et al. GCN Circ. 10317), from 77 s to 852 s after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The light curve can be modelled with a power-law decay with a decay index of alpha=0.58 +/- 0.16. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.10 (+0.29, -0.26). The best-fitting absorption column is 1.7 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 4.1 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 3.8 x 10^-11 (5.7 x 10^-11) erg cm^-2 count^-1. If the light curve continues to decay with a power-law decay index of 0.58, the count rate at T+24 hours will be 0.023 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.7 x 10^-13 (1.3 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00382399. This circular is an official product of the Swift-XRT team.