[vsnet-grb-info 6957] GRB 081121: Enhanced Swift-XRT position

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8541
SUBJECT: GRB 081121: Enhanced Swift-XRT position
DATE:    08/11/22 05:00:10 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at 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 939 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 081121, 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 = 89.2757, -60.6028 which is equivalent
to:

RA (J2000): 05h 57m 6.17s
Dec (J2000): -60d 36' 10.1"

with an uncertainty of 1.7 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
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.

This circular was automatically generated, and is an official product of the
Swift-XRT team.