TITLE: GCN CIRCULAR NUMBER: 6194 SUBJECT: GRB 070311: Swift/UVOT Upper Limits DATE: 07/03/11 14:59:18 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) reports on behalf of the Swift UVOT team: Swift/UVOT observed the field of GRB 070311 (Mereghetti, et al. 2007, GCN Circ. 6189) starting 7004 s after the INTEGRAL/IBAS trigger. UVOT did not detect any source at the location of the infrared afterglow (Covino, et al. 2007, GCN Circ. 6190), 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 7618 7818 197 19.5 B 7004 7203 197 20.5 U 8232 8432 197 20.1 UVW1 8027 8227 197 20.0 UVM2 7822 8022 197 20.0 UVW2 7414 7613 197 20.3 These upper limits are not corrected for the Galactic extinction, corresponding to a reddening of E_{B-V} = 0.76 mag (Schlegel et al. 1998), in the direction of this burst.