TITLE:   GCN CIRCULAR
NUMBER:  4128
SUBJECT: GRB051021B: Swift XRT Position
DATE:    05/10/22 08:03:04 GMT
FROM:    Judith Racusin at PSU  <racusin@astro.psu.edu>

J. Racusin, D. Morris, C. Pagani, D. Burrows, A. Retter (PSU), N. Gehrels 
(GSFC) on behalf of the Swift XRT team:

The Swift XRT began observing GRB 051021B (trigger #160672, Retter et al., 
GCN 4126) at 23:33:14 UT, but was unable to obtain an on-board centroid. 
Analysis of the first 2 orbits of the ground data reveal a previously 
uncatalogued, fading X-ray source at the following coordinates:

RA(J2000) = 08 24 11.8
Dec(J2000) = -45 32 30.8

We estimate an uncertainty of 4 arcseconds (90% containment), including 
corrections for the XRT boresight offset.  This position lies 88 
arcseconds from the BAT position reported in GCN 4126.