TITLE: GCN CIRCULAR NUMBER: 23888 SUBJECT: GRB 190211A: Swift-XRT refined Analysis DATE: 19/02/12 04:12:55 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), K.L. Page (U. Leicester) and F.E. Marshall report on behalf of the Swift-XRT team: We have analysed 9.4 ks of XRT data for GRB 190211A (Marshall et al. GCN Circ. 23883), from 205 s to 24.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 196.6588, +41.9671 which is equivalent to: RA (J2000): 13 06 38.10 Dec(J2000): +41 58 01.5 with an uncertainty of 3.5 arcsec (radius, 90% confidence). The light curve can be modelled with an initial power-law decay with an index of alpha=0.15 (+0.16, -0.21), followed by a break at T+1088 s to an alpha of 1.11 (+0.05, -0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.94 (+0.11, -0.10). The best-fitting absorption column is 7.1 (+2.6, -2.4) x 10^20 cm^-2, in excess of the Galactic value of 1.7 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 3.4 x 10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 7.1 (+2.6, -2.4) x 10^20 cm^-2 Galactic foreground: 1.7 x 10^20 cm^-2 Excess significance: 3.7 sigma Photon index: 1.94 (+0.11, -0.10) If the light curve continues to decay with a power-law decay index of 1.11, the count rate at T+24 hours will be 9.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.2 x 10^-13 (3.7 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00888648. This circular is an official product of the Swift-XRT team.