TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3851
SUBJECT: Swift/UVOT UV Photometry of GRB 050820B
DATE:    05/08/22 04:57:22 GMT
FROM:    Margaret Chester at PSU  <chester@astro.psu.edu>

M. Chester (PSU), M. Page (UCL-MSSL), F. Marshall (GSFC), P. Roming (PSU),
D. Hinshaw (GSFC-SPSYS), P. Meszaros (PSU), N. Gehrels (GSFC)
on behalf of the Swift UVOT team.


Swift/UVOT observed GRB 050820B in its UV filters only, due to the 
presence of a
V=4.5 star in its field of view.  The afterglow was not detected at the 
XRT position.
5-sigma upper limits are:


Filter     Magnitude      Exp (s)   T_start    T_stop
UVM2         >19.1         100       1987       2087
UVW1         >19.0         100       2091       2191
UVW2         >19.3         100       2198       2298

where T_start and T_stop are in seconds after the trigger (Page et al. 
GCN 3839).