TITLE: GCN CIRCULAR NUMBER: 28859 SUBJECT: GRB 201104A: Swift-XRT observations DATE: 20/11/06 17:46:49 GMT FROM: Boris Sbarufatti at PSU V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (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 201104A (Ohno et al. GCN Circ. 28828) in a series of observations tiled on the sky. The total exposure time is 4.7 ks, distributed over 3 tiles; the maximum exposure at a single sky location was 2.4 ks. The data were collected between T0+67.6 ks and T0+80.9 ks, and are entirely in Photon Counting (PC) mode. One uncatalogued X-ray source has been detected, it is not above the RASS limit or shows definitive signs of fading. Furthermore, it is coincident with a known optical source and the XRT data are possibly affected by stray light. Therefore we believe that XRT has not detected any viable candidate afterglow. Details of the sources are given below: Source 3: RA (J2000.0): 80.9041 = 05:23:36.99 Dec (J2000.0): -71.0096 = -71:00:34.6 Error: 4.1 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (5.3 [+2.7, -2.0])e-3 ct s^-1 Distance: 664 arcsec from Fermi/LAT position. Flux: (1.53 [+0.77, -0.59])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) A catalogued source was also detected inside the LAT error circle, and two more sources were detected outside of it. The 3 sigma upper limit at the LAT GRB position is 7.6×10-3 ct s-1. The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00094. This circular is an official product of the Swift-XRT team.