{
  "eventId": "GRB 250331B",
  "subject": "GRB 250331B: Enhanced Swift-XRT position",
  "bibcode": "2025GCN.39974....1O",
  "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 824 s of XRT Photon Counting mode data and 1 UVOT\nimages for GRB 250331B, 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 = 71.37215, +43.81257 which is equivalent\nto:\n\nRA (J2000): 04h 45m 29.32s\nDec (J2000): +43d 48' 45.2\"\n\nwith an uncertainty of 3.6 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.\n",
  "circularId": 39974,
  "createdOn": 1743434571136,
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "submittedHow": "email"
}