TITLE: GCN CIRCULAR NUMBER: 14721 SUBJECT: GRB 130528A: Swift/UVOT Upper Limits DATE: 13/05/29 14:39:16 GMT FROM: Massimiliano de Pasquale at MSSL-UCL M. De Pasquale (MSSL-UCL) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130528A 75 s after the BAT trigger (D'Elia et al., GCN Circ. 14711). No optical afterglow consistent with the enhanced XRT position (Goad et al. GCN Circ. 14714) 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 75 225 147 >20.3 u_FC 287 537 246 >19.5 white 75 18737 1239 >21.7 v 617 11553 1245 >19.9 b 543 18247 1356 >20.8 u 287 17334 1583 >21.0 w1 667 22765 1443 >20.7 m2 641 12459 1179 >20.7 w2 592 7143 491 >20.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.16 in the direction of the burst (Schlegel et al. 1998).