{
  "subject": "GRB 171004A: Enhanced Swift-XRT position",
  "eventId": "GRB 171004A",
  "bibcode": "2017GCN.21970....1O",
  "createdOn": 1507138341000,
  "circularId": 21970,
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "email": "pae9@leicester.ac.uk",
  "body": "J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) \nreport on behalf of the Swift-XRT team.\n\nUsing 2218 s of XRT Photon Counting mode data and 2 UVOT\nimages for GRB 171004A, we find an astrometrically corrected X-ray\nposition (using the XRT-UVOT alignment and matching UVOT field sources\nto the USNO-B1 catalogue): RA, Dec = 139.16941, +52.69319 which is equivalent\nto:\n\nRA (J2000): 09h 16m 40.66s\nDec (J2000): +52d 41' 35.5\"\n\nwith an uncertainty of 1.4 arcsec (radius, 90% confidence).\n\nThis position may be improved as more data are received. The latest\nposition can be viewed at http://www.swift.ac.uk/xrt_positions. Position\nenhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans\net al. (2009, MNRAS, 397, 1177).\n\nThis circular was automatically generated, and is an official product of the\nSwift-XRT team."
}