TITLE: GCN CIRCULAR NUMBER: 6683 SUBJECT: GRB070729: Swift/UVOT upper limits DATE: 07/07/29 16:17:07 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara (PSU), C. Guidorzi (U.Bicocca & INAF-OAB) report on behalf of the Swift-UVOT team: The Swift/UVOT observed the field of GRB070729 (trigger=286373) starting 2007-0729 at 00:27:24, 91 s after the BAT trigger (Guidorzi et al. 2007, GCN Circ. 6678). We do not find any new source in any of the UVOT observations inside the refined XRT error circle (Guidorzi 2007, GCN Circ. 6782). The 3-sigma upper limits (in the UVOT photometric system, Breeveld et al., GCN Circ. 6614)for detecting a source inside the XRT error circle in the first finding chart (FC) exposure and the co-added frames (including the finding chart) are listed below: Filter Tstart Tstop Exposure Magnitude (s) (s) (s) (3-sigma UL) White FC 91 191 99.7 20.27 White 91 6079 491 21.30 v 200 33740 1767 20.45 b 4241 19519 1163 20.97 u 4036 25507 2828 21.12 uvw1 3831 24911 3049 21.53 uvm2 606 27229 2764 21.34 uvw2 4652 28966 2164 21.46 The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.02 mag in the direction of the burst (Schlegel et al. 1998).