TITLE:   GCN CIRCULAR
NUMBER:  25286
SUBJECT: GRB 190804B: Swift-XRT afterglow detection
DATE:    19/08/08 08:43:25 GMT
FROM:    Andy Beardmore at U Leicester  <ab271@leicester.ac.uk>

J.P. Osborne (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (ASDC),
V. D'Elia (ASDC), A. Tohuvavohu (PSU), J.A. Kennea (PSU), B. Sbarufatti
(PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
MAXI-detected burst GRB 190804B (Sato et al. GCN Circ. 25262). The
observations now extend from T0+37.2 ks to T0+273.4 ks. 

Of the sources reported by Osborne et al. (GCN Circ. 25273), "Source 2"
has faded from 1.1e-01 count/s to 1.1e-03 count/s between observations
and is	believed to be the afterglow.  The position of this source
(astrometrically enhanced by using the XRT-UVOT alignment and matching
UVOT field sources to the USNO-B1 catalogue) is RA, Dec=240.0251,
-44.7816 which is equivalent to:

RA (J2000): 16:00:6.02
Dec(J2000): -44:46:53.9

with an uncertainty of 3.8 arcsec (radius, 90% confidence). Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and
Evans et al. (2009, MNRAS, 397, 177). This position is 5.6 arcmin from
the MAXI position.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020916.
The results of the full analysis of the tiled XRT observations are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00082.

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