TITLE: GCN CIRCULAR NUMBER: 41472 SUBJECT: GRB 250821A: Enhanced Swift-XRT position DATE: 25/08/21 18:23:49 GMT FROM: Phil Evans at U of Leicester pae9@star.le.ac.uk
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1629 s of XRT Photon Counting mode data and 2 UVOT images for GRB 250821A, 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 = 358.43974, -28.65327 which is equivalent to:
RA (J2000): 23h 53m 45.54s Dec (J2000): -28d 39' 11.8"
with an uncertainty of 2.6 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.
View this GCN Circular online at https://gcn.nasa.gov/circulars/41472. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...