TITLE: GCN CIRCULAR NUMBER: 12406 SUBJECT: GRB 110928A: Swift/UVOT Upper Limits DATE: 11/09/28 20:38:28 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110928A 3342 s after the BAT trigger (Hoversten et al., GCN Circ. 12394). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 12402) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 3342 3492 147 >20.2 white 3342 4723 344 >21.0 v 3499 3698 197 >19.1 b 4319 4518 197 >21.0 u 4114 4313 197 >20.8 w1 3909 4108 197 >20.3 m2 3704 3903 197 >19.9 w2 4729 4929 197 >21.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).