TITLE: GCN CIRCULAR NUMBER: 18456 SUBJECT: GRB 151022A: Swift/UVOT Upper Limits DATE: 15/10/23 20:11:49 GMT FROM: Mike Siegel at PSU/Swift MOC B. G. Balzer (PSU) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 151022A 304 s after the BAT trigger (D'Avanzo et al., GCN Circ. 18436). No optical afterglow consistent with the XRT position (Evans GCN Circ. 18438) 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 304 454 147 >21.2 white 304 7836 902 >22.0 v 461 8247 646 >20.1 b 560 7632 430 >21.0 u 535 7426 430 >21.2 w1 510 12075 553 >19.7 m2 486 8452 646 >20.3 w2 609 8042 627 >20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.56 in the direction of the burst (Schlegel et al. 1998).