TITLE: GCN CIRCULAR NUMBER: 20050 SUBJECT: GRB 161014A: Swift-XRT refined Analysis DATE: 16/10/15 14:31:20 GMT FROM: Phil Evans at U of Leicester B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers (PSU) and J.L. Racusin report on behalf of the Swift-XRT team: We have analysed 5.5 ks of XRT data for GRB 161014A (Racusin et al. GCN Circ. 20035), from 108 s to 34.8 ks after the BAT trigger. The data comprise 48 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. Using 5612 s of PC mode data and 8 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 332.64760, +7.46873 which is equivalent to: RA (J2000): 22h 10m 35.42s Dec(J2000): +07d 28' 07.4" with an uncertainty of 1.4 arcsec (radius, 90% confidence). The light curve can be modelled with an initial power-law decay with an index of alpha=0.45 (+/-0.12), followed by a break at T+1757 s to an alpha of 1.59 (+0.14, -0.13). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.83 (+0.11, -0.10). The best-fitting absorption column is 1.5 (+0.9, -0.8) x 10^22 cm^-2, at a redshift of 2.823, in addition to the Galactic value of 7.5 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 (4.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 7.5 x 10^20 cm^-2 Intrinsic column: 1.5 (+0.9, -0.8) x 10^22 cm^-2 at z=2.823 Photon index: 1.83 (+0.11, -0.10) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00717500. This circular is an official product of the Swift-XRT team.