TITLE: GCN CIRCULAR NUMBER: 20482 SUBJECT: GRB 170117A: Swift-XRT observations DATE: 17/01/18 21:43:57 GMT FROM: Andrea Melandri at INAF-OAB J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), 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 Swift/BAT-detected burst GRB 170117A, collecting 2.9 ks of Photon Counting (PC) mode data between T0+86.3 ks and T0+116.0 ks. No X-ray sources have been detected consistent with being within 296 arcsec of the Swift/BAT position. The 3-sigma upper limit in the field ranges from ~0.003 to ~0.004 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.3e-13 to 1.8e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). An uncatalogued was detected, however this was too far from the GRB position to be the afterglow. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00020728. This circular is an official product of the Swift-XRT team.