[vsnet-grb-info 5358] GRB 071104: Possible Swift UVOT Afterglow Candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7044
SUBJECT: GRB 071104: Possible Swift UVOT Afterglow Candidate
DATE:    07/11/05 05:56:30 GMT
FROM:    Stefan Immler at NASA/GSFC  <immler at milkyway.gsfc.nasa.gov>

S. Immler (NASA/CRESST/GSFC) reports on behalf of the Swift
UVOT team:

Swift UVOT started observing the field of the SuperAGILE burst GRB
071104 (Donnarumma et al., GCN Circ. 7042), 20.6 ks after the AGILE
trigger. In the first 120-s and co-added 5037-s of data obtained in the 
white
filter, a possible UVOT afterglow candidate is found consistent with the
XRT position (Page, GCN 7043), with a magnitude of 20.6+/-0.1 mag,
overlaying the coincidence-loss structure of a nearby bright star.

The value quoted above is not corrected for the expected Galactic
extinction corresponding to a reddening of E_{B-V} = 0.54 mag in the
direction of the burst (Schlegel et al. 1998).

Further analysis is required due to possible contamination with the
coincidence-loss structure of the nearby star and the high source
density of the field in the Galactic plane.