TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4674
SUBJECT: GRB060204B: Swift/UVOT refined analysis
DATE:    06/02/05 06:56:16 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A.Cucchiara, A Falcone, S. Hunsberger (PSU),F. Marshall (GSFC),
P. Boyd (GSFC-UMBC), N. Gehrels (GSFC), on behalf of
the Swift UVOT team.

The Swift/UVOT began taking data on the field of GRB 060204B at
14:34:24 UT on 2006-02-04, 101 s after the BAT trigger (Falcone et al.,
GCN 4655). We detected an uncatalogued object cosistent with   
the xrt position reported by Falcone et al. (GCN 4669)
and Guidorzi et al. (GCN 4661) in our first 200 exposure V image.
We have no afterglow detection in summed images in
any other filter within the refined XRT error circle down to the
following 3-sigma magnitude upper limits.

Filter       T_range(s)      Exp(s)      mag             coadd
V             101-301           200       19.43+/- 0.50    N
B             307-703           396       >20.12              Y
U             4086-4890         91       >19.66              Y
UVW1     4062-4746        98       >18.90              Y
UVM2     4020-4722        95       >18.98              Y
UVW2     427-4237          97       >19.11              Y

These magnitudes are uncorrected for Galactic extinction;
E(B-V) = 0.018.

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