TITLE: GCN CIRCULAR NUMBER: 29018 SUBJECT: GRB 201208A: Swift-XRT afterglow detection DATE: 20/12/09 19:48:17 GMT FROM: Aaron Tohuvavohu at U Toronto A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/LAT-detected burst GRB 201208A (Dirirsa et al. GCN Circ. 29003), collecting 5.0 ks of Photon Counting (PC) mode data between T0+70.4 ks and T0+111.4 ks. Four uncatalogued X-ray sources are detected, of which one ("Source 2") is above the 2SXPS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. Using 2046 s of PC mode data and 2 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 = 158.32352, -28.71989 which is equivalent to: RA (J2000): 10h 33m 17.64s Dec(J2000): -28d 43' 11.6" with an uncertainty of 3.1 arcsec (radius, 90% confidence). This position is 112 arcsec from the Fermi/LAT position. The results of the XRT-team automatic analysis of the likely afterglow are at https://www.swift.ac.uk/ToO_GRBs/00021405/Source2.php. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021405. This circular is an official product of the Swift-XRT team.