TITLE: GCN CIRCULAR NUMBER: 8488 SUBJECT: UVOT/Swift observations of GRB081105 DATE: 08/11/06 16:07:53 GMT FROM: Patricia Schady at MSSL/Swift P.A. Curran (UCL-MSSL), P. Schady (UCL-MSSL) and J. Cummings (GSFC/UMBC), on behalf of the Swift/UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of the Swift-BAT and IPN localization GRB 081105 (#333811; Cummings et al., GCN 8484) ~16 hours after the BAT trigger. No afterglow is detected at the XRT position (Beardmore et al., GCN 8487) in any filter. The 3-sigma limiting magnitudes in each of the observed UVOT filters are as follows: Filter T_start(dys) Exp(s) Mag UL (3sig) white 0.67 159 > 20.76 v 0.81 630 > 19.92 b 0.66 885 > 21.05 u 0.74 224 > 19.92 uvw1 0.73 886 > 20.75 uvw2 0.89 886 > 21.02 The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). They are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998).