[AAVSO-HEN] GRB 080905A: Enhanced Swift-XRT position

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  8203
SUBJECT: GRB 080905A: Enhanced Swift-XRT position
DATE:    08/09/08 15:06:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9 at star.le.ac.uk>

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

Using more data than were available at the time of de Ugarte Postigo et
al. (GCN Circ 8195), the UVOT-enhanced X-ray position of GRB 080905A has
been improved to RA, Dec = 287.67390, -18.88022 which is equivalent to:

RA (J2000): 19 10 41.74
Dec (J2000): -18 52 48.8

with an uncertainty of 1.6 arcsec (90% confidence). This position lies
1.5" from the optical counterpart identified by Malesani et al (GCN
Circ. 8190), consistent with that position.

Position enhancement, using the XRT-UVOT alignment and matching to the
USNO-B1 catalogue, 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.