GCN Circular 18689
M. De Pasquale (PSU) and P. Evans (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of MAXI-detected GRB 151212A (Nahakira et al., GCN Circ. 18685) 42183 s after the trigger. No optical afterglow consistent with the XRT source given by Evans et al. (GCN Circ 18687) is detected in the UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the summed UVOT exposures is: Filter T_start(s) T_stop(s) Exp(s) Mag u 42183 48392 2939 >21.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).