TITLE: GCN CIRCULAR NUMBER: 13161 SUBJECT: GRB 120328A: Swift/UVOT Upper Limits DATE: 12/03/28 16:02:39 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU) and C. Pagani (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120328A 78 s after the BAT trigger (Pagani et al., GCN Circ. 13147). No optical afterglow consistent with the enhanced XRT position (Beardmore el al., GCN Circ. 13153) 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 78 228 147 >20.6 u_FC 290 540 246 >19.6 white 78 764 186 >20.5 v 621 813 39 >18.2 b 547 739 39 >19.1 u 290 715 265 >19.8 w1 670 862 39 >18.9 w2 769 789 20 >18.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.73 in the direction of the burst (Schlegel et al. 1998).