[vsnet-grb-info 14645] GRB 140311A: Enhanced Swift-XRT position

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15959
SUBJECT: GRB 140311A: Enhanced Swift-XRT position
DATE:    14/03/12 09:56:51 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at leicester.ac.uk>

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

Using 1977 s of XRT Photon Counting mode data and 4 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 =
209.30516, 0.64193 which is equivalent to:

RA (J2000):  13 57 13.24
Dec (J2000): +00 38 31.0

with an uncertainty of 1.8 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 position is 0.5 arc sec from the optical counterpart reported by
Xu et al (GCN Circ. 15947), thus we believe this is the X-ray afterglow.

This circular is an official product of the Swift-XRT team.