GCN Circular 27840
F. E. Marshall (NASA/GSFC) and E. Ambrosi (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200528A 81 s after the BAT trigger (Ambrosi et al., GCN Circ. 27832). No optical afterglow consistent with the enhanced XRT position (Evans et al. GCN Circ. 27836) 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 81 231 147 >21.1 u 293 305 12 >18.7 v 5743 5942 197 >18.8 b 5127 5327 169 >20.7 uvw2 5538 5738 197 >21.0 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).