TITLE:   GCN CIRCULAR
NUMBER:  8255
SUBJECT: GRB 080916C: Enhanced XRT position 
DATE:    08/09/17 09:01:33 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans, J.P. Osborne, A.P. Beardmore and M.R. Goad, (U. Leicester)
report on behalf of the Swift-XRT team.

Using 1310 s of XRT Photon Counting mode data and 1 UVOT images, we find an 
astrometrically corrected X-ray position (using the XRT-UVOT alignment and 
matching to the USNO-B1 catalogue): RA, Dec = 119.84706, -56.63788 which is 
equivalent to:

RA (J2000): 07 59 23.29
Dec (J2000): -56 38 16.4

with an uncertainty of 2.1 arcsec (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 is an official product of the Swift-XRT team.