TITLE: GCN CIRCULAR NUMBER: 6185 SUBJECT: GRB 070309: Swift/UVOT Upper Limits DATE: 07/03/09 20:54:28 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) and Cucchiara A. (PSU) report on the behalf of the Swift UVOT team: Swift/UVOT observed the field of GRB 070309 (Paizis, et al. 2007, GCN Circ. 6182) starting 13,906 s after the INTEGRAL/IBAS trigger. UVOT did not detect any source inside the INTEGRAL error circle, relative to the DSS, down to the following 3 sigma upper limits. Filter t_start(s) t_stop(s) Exp(s) Mag 3-sig UL V 14,525 14,868 274 19.3 B 14,215 14,365 147 20.0 U 14,061 14,211 147 19.7 UVW1 13,906 14,056 147 19.6 UVM2 14,930 15,080 147 19.5 UVW2 14,371 14,446 147 19.8 These upper limits are not corrected for the Galactic extinction, corresponding to a reddening of E_{B-V} = 1.46 mag (Schlegel et al. 1998), in the direction of this burst. We note that this burst lies in the Galactic plane towards the Galactic centre and the field is very crowded.