TITLE: GCN CIRCULAR NUMBER: 22023 SUBJECT: GRB 171010B: Swift-XRT afterglow detection DATE: 17/10/18 13:07:12 GMT FROM: Kim Page at U.of Leicester A. Melandri (INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has conducted further observations of the field of the Swift/BAT-detected burst GRB 171010B (Palmer et al. GCN Circ. 21995). The observations now extend from T0+91.1 ks to T0+614.5 ks. Of the sources reported by Sbarufatti et al. (GCN Circ. 22009), "Source 2" is believed to be the afterglow. The position of this source is RA, Dec=34.1342, -54.3915 which is equivalent to: RA (J2000): 02:16:32.20 Dec(J2000): -54:23:29.2 with an uncertainty of 5.6 arcsec (radius, 90% confidence). This position is 71 arcsec from the Swift/BAT position. The light curve can be modelled with a power-law decay with a decay index of alpha=0.8 (+0.6, -0.4). The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020780. The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00020780. This circular is an official product of the Swift-XRT team.