TITLE:   GCN CIRCULAR
NUMBER:  11017
SUBJECT: GRB 100728B:  Enhanced Swift-XRT position
DATE:    10/07/28 14:29:45 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

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

Using 820 s of XRT Photon Counting mode data and 2 UVOT
images, 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 = 44.05620, 0.28120 which is equivalent to:

RA (J2000):  02 56 13.48
Dec (J2000): +00 16 52.5

with an uncertainty of 2.0 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 is an official product of the Swift-XRT team.