TITLE: GCN CIRCULAR NUMBER: 23297 SUBJECT: GRB 181002A: Swift/UVOT Upper Limits DATE: 18/10/03 10:48:04 GMT FROM: Sam Emery at MSSL-UCL S.W.K. Emery (UCL-MSSL) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 181002A 144 s after the BAT trigger (Gropp et al., GCN Circ. 23290). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 23292) 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 144 294 147 >20.8 u_FC 302 552 246 >20.3 white 144 1008 334 >20.7 v 632 1058 58 >17.9 b 558 751 39 >18.6 u 302 726 265 >20.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.60 in the direction of the burst (Schlegel et al. 1998).