TITLE: GCN CIRCULAR NUMBER: 20909 SUBJECT: GRB 170318B: Prompt enhanced Swift-XRT position DATE: 17/03/18 16:17:21 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 170318B, we find an enhanced XRT position of the afterglow: RA, Dec: 284.3062, 6.2994 which is equivalent to: RA (J2000) = 18 57 13.49 Dec (J2000) = +06 17 57.9 with an uncertainty of 2.1 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/743086. Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team.