TITLE: GCN CIRCULAR NUMBER: 6504 SUBJECT: GRB 070611: Swift/UVOT Observations DATE: 07/06/11 20:39:22 GMT FROM: Wayne Landsman at GSFC/SSAI W. Landsman (NASA/GSFC), F.E. Marshall (NASA/GSFC) and M.C. Stroh (PSU) report on behalf of the Swift/UVOT team. UVOT took a finding chart exposure of 98 seconds of the field of GRB 070611 (Stroh et al., GCN 6494) with the White (160-650 nm) filter starting 3295 seconds after the BAT trigger. The UVOT finding chart was delayed due to an Earth limb constraint. We detect the afterglow candidate reported by Rykoff et al. (GCN 6497), and measure a position of RA(J2000) = 00 07 58.01 Dec(J2000) = -29 45 20.0 with an estimated 90% uncertainty of 0.5". Because of a configuration problem, most subsequent UVOT images do not include the afterglow position, but there is a 3.5 sigma detection in a subsequent image taken with the UVW1 (2600 A) filter. Magnitudes and 3 sigma upper limits are reported below. Filter T_start(sec) Exposure(sec) Mag White 3295 98 19.12 ± 0.11 UVW1 4632 197 19.51 ± 0.31 UVW1 10046 886 >20.72 (3 sigma) UVM2 4427 197 >19.64 (3 sigma) UVW2 4019 197 >19.97 (3 sigma) The lack of detections in the UVM2 (2260 A) and UVW2 (1930 A) filters are consistent with the redshift of z=2.04 reported by Thoene et al. (GCN 6499). No correction has been made for the expected reddening of E(B-V) = 0.012 [GCN OPS NOTE(11jun07): Per author's request, the Subject-line was corrected; "070610" was changed to "070611".]