TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4994
SUBJECT: GRB060421: Swift/UVOT observations
DATE:    06/04/21 17:04:13 GMT
FROM:    Peter Brown at PSU  <pbrown@astro.psu.edu>

P. J. Brown (PSU), M. R. Goad (U Leicester),
S. T. Holland (GSFC/USRA), & P. O'Brien (U Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began taking settled exposures of the
field of GRB0604213 at 2006-04-21 00:40:48,
84 s after the BAT trigger (Goad et al., GCN 4985).
Within the revised XRT error circle (Goad, Page,
& Burrows GCN 4992) we detect a V=19.0 +/- 0.2 source at
22:54:32.18, +62:43:49.5 (+/- 1") which is coincident
with 2MASS 22543217+6243493 and also visible in the
DSS.  This source does not vary over ~5 hours of
observations and is not considered an afterglow
candidate.

We do not detect this or any other sources in
summed images from any of the other filters down
to the following three-sigma upper limits.

Filter  T_range(s)  Exp(s) 3sig_UL

V        84-17355   1700   19.0
B       562-23873   1116   20.6
U       538-23145   2035   20.5
UVW1    514-22233   2204   20.2
UVM2    490-18091   2074   20.4
UVW2    578-16442   1318   20.2

These upper limits are uncorrected for extinction.
The Galactic latitude is +2.83 degrees and the
Schlegel et al. (1998) reddening in this direction
is E(B-V)=1.28 mag.  As noted in GCN 4985 the
Cepheus OB3 molecular cloud association in our Galaxy
is near this line of sight.