TITLE: GCN CIRCULAR NUMBER: 20910 SUBJECT: GRB 170318B: Enhanced Swift-XRT position DATE: 17/03/18 17:06:50 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 839 s of XRT Photon Counting mode data and 1 UVOT images for GRB 170318B, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 284.30611, +6.29924 which is equivalent to: RA (J2000): 18h 57m 13.47s Dec (J2000): +06d 17' 57.3" with an uncertainty of 1.9 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.