TITLE: GCN CIRCULAR NUMBER: 11499 SUBJECT: GRB 101225A: Swift/UVOT Detection DATE: 10/12/26 16:20:36 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 101225A 1387 s after the BAT trigger (Racusion et al., GCN Circ. 11493). We find a marginal detection in the later data consistent with the enhanced XRT position (Evans et al., GCN Circ. 11497). Preliminary 3-sigma upper limits and magnitudes using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag V 1387 1705 58 >19.11 V 5572 29944 2601 >21.40 B 1485 1655 38 >19.84 B 5161 28991 3933 21.73+-0.29 U 1460 1630 38 >19.35 U 4955 7534 507 >20.68 UVW1 1435 1754 58 >19.25 UVW1 5982 7413 393 20.58+-0.37 UVM2 1410 1729 58 >18.74 UVM2 5777 7208 393 20.12+-0.34 UVW2 1512 1680 38 >18.82 UVW2 5367 6798 393 19.67+-0.22 UVW2 11650 12550 885 20.35+-0.22 UVW2 17470 18370 885 19.62+-0.15 UVW2 23218 29897 1771 20.10+-0.14 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).