TITLE: GCN CIRCULAR NUMBER: 18008 SUBJECT: GRB 150710A: Swift/UVOT Upper Limits DATE: 15/07/10 20:15:24 GMT FROM: Massimiliano de Pasquale at IASF-Palermo M. De Pasquale (UCL-MSSL) and M.G. Bernardini (INAF/OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150710A 54 s after the BAT trigger (Bernardini et al., GCN Circ. 18000). No optical afterglow consistent with the position of the XRT sources (Bernardini et al., GCN Circ 18005) 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 54 204 147 >20.6 u_FC 266 516 246 >19.9 white 54 1017 334 >21.1 v 595 1050 41 >18.1 b 521 714 39 >19.1 u 266 516 285 >20.0 uw1 645 837 39 >18.5 um2 620 812 39 >18.2 uw2 571 1043 58 >19.0 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).