TITLE: GCN CIRCULAR NUMBER: 19664 SUBJECT: GRB 160705B: Swift/UVOT Upper Limits DATE: 16/07/06 20:47:42 GMT FROM: Sam Emery at MSSL-UCL S.W.K. Emery (UCL-MSSL) and J. K. Cannizzo (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160705B 149 s after the BAT trigger (Cannizzo et al., GCN Circ. 19657). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 19659) or the LT and RATIR position (Guidorzi et al. GCN 19658; Watson et al. GCN Circ. 19663) 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 149 298 147 >20.6 u_FC 307 557 246 >19.9 white 4780 6415 393 >21.0 v 5191 11327 1082 >19.9 b 6011 6210 197 >20.1 w1 12239 12529 285 >20.0 m2 11333 12232 886 >20.7 w2 6421 6603 179 >19.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).