TITLE: GCN CIRCULAR NUMBER: 26190 SUBJECT: GRB 191106A: Swift-XRT refined Analysis DATE: 19/11/06 21:28:30 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U. Toronto), J.A. Kennea (PSU), B. Sbarufatti (PSU) and F.E. Marshall report on behalf of the Swift-XRT team: We have analysed 6.3 ks of XRT data for GRB 191106A (Marshall et al. GCN Circ. 26177), from 106 s to 13.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The best available XRT position (using the promptly downlinked event data, the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 269.3356, 46.0353 which is equivalent to: RA (J2000): 17 57 20.55 Dec(J2000): +46 02 06.9 with an uncertainty of 2.3 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=3.37 (+0.33, -0.30). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 (+/-0.6). The best-fitting absorption column is 3.1 (+3.1, -2.1) x 10^21 cm^-2, in excess of the Galactic value of 4.4 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.1 (+3.1, -2.1) x 10^21 cm^-2 Galactic foreground: 4.4 x 10^20 cm^-2 Excess significance: 2.1 sigma Photon index: 2.1 (+/-0.6) If the light curve continues to decay with a power-law decay index of 3.37, the count rate at T+24 hours will be 7.4 x 10^-10 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x 10^-20 (4.1 x 10^-20) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00933515. This circular is an official product of the Swift-XRT team.