TITLE:   GCN CIRCULAR
NUMBER:  43456
SUBJECT: GRB 260117A: Swift-XRT afterglow detection
DATE:    26/01/19 20:06:20 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB),
D.N. Burrows (PSU), S. Lanava (PSU), S. Dichiara (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester)
reports on behalf of the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
SVOM/ECLAIRs-detected burst GRB 260117A. The observations now extend
from T0+12.5 ks to T0+153.1 ks and have a total exposure time of 5.7
ks.

Of the sources previously reported, "Source 1" is fading with >3-sigma
significance, and is therefore likely the GRB afterglow. Using 1064 s
of PC mode data and 1 UVOT image, we find an enhanced XRT position
(using the XRT-UVOT alignment and matching UVOT field sources to the
USNO-B1 catalogue): RA, Dec = 188.13864, +43.91274 which is equivalent
to:

RA (J2000): 12h 32m 33.27s
Dec(J2000): +43d 54' 45.9"

with an uncertainty of 4.9 arcsec (radius, 90% confidence). This
position is 2.5 arcmin from the SVOM/ECLAIRs position, and 0.2 arcsec
from the SVOM/VT optical candidate reported in GCN Circ. 43411.  The
source is fading with alpha >0.2.

The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/xrt_products/00021898.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021898.

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