TITLE: GCN CIRCULAR NUMBER: 35308 SUBJECT: GRB231205B: Swift/UVOT Upper Limits DATE: 23/12/08 17:38:53 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18@psu.edu> M. H. Siegel (PSU) and P. A. Evans (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 231205B 216 s after the BAT trigger (Evans et al., GCN Circ. 35269). No optical afterglow consistent with the XRT position (Osborne et al. 35275) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 237 387 147 >21.3 white 237 536 167 >21.3 v 216 414 33 >18.6 b 492 512 19 >19.6 u 468 487 19 >18.2 w1 443 463 19 >19.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.204 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/35308. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...