[vsnet-grb-info 8449] Correction: GRB 090929B: Enhanced Swift-XRT position

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9965
SUBJECT: Correction: GRB 090929B: Enhanced Swift-XRT position
DATE:    09/09/29 14:09:34 GMT
FROM:    Kim Page at U.of Leicester  <kpa at star.le.ac.uk>

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

GCN Circ. 9964 referred to GRB 090929 when, in fact, the position given 
is for GRB 090929B (GCN Circ. 9963). The correct text should read

Using 2438 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090929B, 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 = 117.72015, -0.65764 which is 
equivalent
to:

RA (J2000): 07h 50m 52.84s
Dec (J2000): -00d 39' 27.5"

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).

We apologise for any confusion.