GCN Circular 13449

A. A. Breeveld (MSSL-UCL) and M. J. Page (MSSL-UCL) report on behalf of 
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 120711B
260 s after the BAT trigger (Page et al., GCN Circ. 13431
Not found
 
 
).
No optical afterglow consistent with the XRT position (Page et al., GCN 
Circ. 13431
Not found
 
 
) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           260          410          147         >21.7
white              260          734          186         >21.8
v                  417          784           58         >18.9
b                  516          710           39         >19.8
u                  491          858           58         >19.5
w1                 466          833           58         >18.9
m2                 441          809           58         >19.3
w2                 566         6472          208         >20.2

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 1.13 in the direction of the 
burst (Schlegel et al. 1998).