TITLE: GCN CIRCULAR NUMBER: 10490 SUBJECT: GRB 100316A: Enhanced Swift-XRT position DATE: 10/03/16 08:21:20 GMT FROM: Phil Evans at U of Leicester P.A. Evans reports on behalf of the Swift-XRT team Using 1129 s of XRT Photon Counting mode data and 2 UVOT images, 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 = 251.98150, 71.82780 which is equivalent to: RA (J2000): 16 47 55.56 Dec (J2000): +71 49 40.0 with an uncertainty of 2.9 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 is an official product of the Swift-XRT team.