TITLE: GCN CIRCULAR NUMBER: 13533 SUBJECT: GRB 120728A: Swift/UVOT Upper Limits DATE: 12/07/29 13:31:20 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120728A 148 s after the BAT trigger (Cummings et al., GCN Circ. 13525). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ.13528) 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 u_FC 148 398 246 >19.5 v 456 17454 1356 >20.6 b 404 24174 2261 >22.3 u 148 23261 2438 >21.0 w1 505 19107 1200 >20.8 m2 480 18359 1357 >21.0 w2 430 24878 1735 >21.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.53 in the direction of the burst (Schlegel et al. 1998).