TITLE: GCN CIRCULAR NUMBER: 20169 SUBJECT: GRB 161109A: Swift/UVOT Upper Limits DATE: 16/11/11 15:34:35 GMT FROM: Sam Emery at MSSL-UCL S. W. K Emery (MSSL-UCL) and A. D'Ai (INAF-IASFPA) report on behalf of the Swift/UVOT team: Swift-UVOT performed follow-up observations of the Fermi/LAT-detected burst GRB 161109A (Desiante et al. GCN Circ. 20155) in a series of observations tiled on the sky. Observations were taken in the u band filter between T0+40.4 ks and T0+63.3 ks after the Fermi trigger. Swift/UVOT did not find any new optical counterpart. The 3 sigma upper limits at the position of each of the uncatalogued X-ray sources (Gibson et al. GCN Circ. 20164) are: Source T_start (s) T_end (s) Exposure Time (s) filter 3s UL Source 2 40425 57980 1152 u 20.11 Source 3 40425 57980 1152 u 20.08 Source 6 41245 63272 1121 u 19.22 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).