TITLE: GCN CIRCULAR NUMBER: 6519 SUBJECT: GRB 070612B: Swift/UVOT upper limits DATE: 07/06/12 15:15:50 GMT FROM: Wayne Landsman at GSFC/SSAI W. Landsman (NASA/GSFC) and D. Grupe (PSU) report on behalf of the Swift/UVOT team. The Swift/UVOT observed the field of GRB 070612B starting 3256 s after the BAT trigger (Grupe et al., GCN Circ. 6511). The UVOT observations were delayed due to a Earth-limb constraint. We do not find any source in any of the UVOT observations inside the refined XRT error circle (Grupe et al., GCN Circ. 6514). The 3-sigma upper limits for detecting a source in the first finding chart (FC) exposure and co-added frames are: Filter T_start(s) T_stop(s) Exp(s) Mag (3-sigma UL) Wh (FC) 3256 3356 98 >20.3 Wh 3256 9882 1201 >21.7 V 3238 11624 1113 >20.0 B 4180 5813 393 >20.4 U 3975 5608 393 >20.1 UVW1 3772 5404 393 >20.1 UVM2 3567 5199 393 >20.0 UVW2 4590 10888 1082 >20.9