TITLE: GCN CIRCULAR NUMBER: 11451 SUBJECT: GRB 101213A: Swift/UVOT Upper Limits DATE: 10/12/13 16:52:37 GMT FROM: Wayne Landsman at GSFC/SSAI W. Landsman (NASA/Adnet) and T. Sakamoto (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 101213A 114 s after the BAT trigger (Sakamoto et al., GCN Circ. 11448). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 11450) 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 114 264 147>21.0 u_FC 327 577 246>19.8 white 114 5066 286>21.4 v 3919 4119 197>19.2 b 583 4940 216>20.5 u 327 4733 442>20.4 w1 4329 4529 197>20.3 m2 4124 4323 197>20.4 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998).