TITLE: GCN CIRCULAR NUMBER: 43175 SUBJECT: GRB 251221A: Enhanced Swift-XRT position DATE: 25/12/21 20:38:47 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 1499 s of XRT Photon Counting mode data and 2 UVOT images for GRB 251221A, 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 = 101.42771, +0.73217 which is equivalent to: RA (J2000): 06h 45m 42.65s Dec (J2000): +00d 43' 55.8" with an uncertainty of 2.1 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at https://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/43175. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...