GCN Circular 12618

S. R. Oates (MSSL-UCL) and E. Sonbas (GSFC/USRA/Adiyaman_Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 111204A
143 s after the BAT trigger (Sonbas et al., GCN Circ. 12612
Not found
 
 
).
No optical afterglow consistent with the XRT position 
(Beardmore et al., GCN Circ. 12614
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           143          293          147         >20.4
white              143         5439          541         >21.6
v                 4214         5851          393         >19.6
b                 3599        11889         1054         >20.8
u                  302        11204         1116         >21.3
w1                4624        10291         1133         >20.7
m2                4419        15631          869         >21.1
w2                4009         5646          393         >20.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).