[vsnet-grb-info 3865] GRB061004: Swift/UVOT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5696
SUBJECT: GRB061004: Swift/UVOT optical observations
DATE:    06/10/05 11:38:35 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (UCL-MSSL), H. Ziaeepour (UCL-MSSL) report on behalf
of the Swift UVOT team

The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of
GRB061004 at 19:51:14 UT, ~51 seconds after the initial Swift BAT trigger
(Ziaeepour et al, GCN 5691). No optical counterpart was detected at the
XRT position (Page et al, 6595) within the coadded images or with the V
and white finding charts.

The 3 sigma upper limits are provided for the coadded images and the
finding charts below:


Filter           Start      Stop    Exposure  3SigmaUL
--------------------------------------------------------
WHITE (finding)    68        168        100     18.4
V (finding)       174        574        400     20.0

V                 704      24752       1477     18.9
B                 652      13187        928     19.9
U                 625      18969       1225     20.5
UVW1              604      18895       2121     21.2
UVM2              580      17988       1357     20.4
UVW2              680      24092       1337     20.5
WHITE             665       6706        520     20.3
--------------------------------------------------------


The values quoted above are not corrected for the expected
Galactic extinction of E_{B-V}=0.049.