TITLE: GCN CIRCULAR NUMBER: 10420 SUBJECT: GRB 100213A: Swift/UVOT Upper Limits DATE: 10/02/14 12:39:40 GMT FROM: Peter Curran at MSSL P.A. Curran (MSSL-UCL) and D. Grupe (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 100213A 77s after the BAT trigger (Grupe et al., GCN 10411). No optical afterglow consistent with the XRT position (Beardmore et al., GCN 10418) 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 exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag ------------------------------------------------ white 77 227 147 >20.20 v 59 68 9 >17.19 u 289 366 75 >19.7 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.31 in the direction of the burst (Schlegel et al. 1998).