TITLE: GCN CIRCULAR NUMBER: 8581 SUBJECT: GRB081128: Swift/UVOT Upper Limits DATE: 08/11/29 21:22:41 GMT FROM: Peter Brown at PSU P. J. Brown (PSU) and R. Margutti (Univ. Biococca & OAB) report on behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 081128 starting 206 s after the BAT trigger (Margutti et al., GCN Circ. 8571). We do not detect any source inside the UVOT-enhanced XRT error circle (Evans, et al., GCN Circ. 8573) down to the following 3-sigma upper limits in the finding chart and co-added images: Filter T_start T_stop Exp(s) Mag ------------------------------------------ white 207 356 150 >20.9 white 207 959 308 >21.3 v 363 5643 247 >19.4 b 462 826 58 >19.6 u 437 801 58 >19.3 uvw1 413 777 58 >19.0 uvm2 388 752 58 >18.6 uvw2 512 4429 236 >19.9 white 10015 34512 625 >21.4 v 27370 75499 3535 >21.0 ----------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E(B-V) = 0.05 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627).