TITLE: GCN CIRCULAR NUMBER: 11322 SUBJECT: Subject: GRB 101008: Swift/UVOT Upper Limits DATE: 10/10/08 23:55:17 GMT FROM: Paul Kuin at MSSL N.P.M. Kuin (MSSL/UCL) and W. H. Baumgartner (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 101008 3167 s after the BAT trigger (Baumgartner et al., GCN Circ. 11318). No optical afterglow consistent with the XRT position (Beardmore et al., GCN Circ 11321) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 3167 3316 147 >20.6 white 3167 5372 541 >21.3 v 4147 5752 363 >19.6 b 3531 5167 393 >20.6 u 3326 4962 393 >20.1 w1 4557 4757 197 >20.1 m2 4352 4552 197 >20.3 w2 3943 5577 393 >20.6 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.19 in the direction of the burst (Schlegel et al. 1998).