TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4263
SUBJECT: GRB051111: Swift/UVOT Observations
DATE:    05/11/11 16:51:52 GMT
FROM:    Tracey Poole at MSSL  <tsp@mssl.ucl.ac.uk>

T.S. Poole (UCL-MSSL), T. Sakamoto (GSFC), A.J. Blustin (UCL-MSSL), B.
Hancock (UCL-MSSL) & T.Kennedy (UCL-MSSL) on behalf of the Swift/UVOT team
report:

The Swift-Ultra-Violet/Optical Telescope (UVOT) began observing the field 
of GRB 051111 (BAT Trigger=163438; Sakamoto et al. GCN 4248) at 2005-11-11
7:47:20, 5560 seconds after the burst. We detect a source in the V, B, U 
and UVW1 filters at position RA 23:12:33.17, DEC 18:22:28.80; this 
position was also reported  by Mundell  et. al. (GCN 4250).  The source is 
not detected in the UVM2 or UVW2 filters.

The aperture used for optical observations was 6 arcsec, and 12 arcsec was
used for the ultraviolet observations.  The limiting magnitudes are given 
to a 3 sigma limit.

Filter  T_range         T_exp   Mag
         (sec)           (sec)
V       16298-17198     900     19.33+/-0.35    - source detection
B       11237-12136     900     20.38+/-0.35    - source detection
U       10329-11229     900     20.09+/-0.46    - source detection
UVW1    6467-7153       686     20.25+/-0.85    - source detection
UVM2    5560-11832      1800    20.92           - upper limit
UVW2    12145-12938     793     20.64           - upper limit

Where T_range is time post-trigger, and T_exp is the exposure time of the
observation. Magnitude errors include statistical and systematic errors.

These results were obtained from intital UVOT exposures, and the 
observations of GRB051111 are continuing.

This message may be cited.