TITLE: GCN CIRCULAR NUMBER: 22496 SUBJECT: GRB 180314B: Swift/UVOT Upper Limits DATE: 18/03/15 16:38:44 GMT FROM: Samantha Oates at MSSL S. R. Oates (U.Warwick) 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 180314B 94 s after the BAT trigger (D'Avanzo et al., GCN Circ. 22491). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 22494) 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 94 244 147 >19.6 u_FC 308 558 246 >19.3 white 94 7249 666 >19.7 v 638 7660 607 >18.4 b 563 11580 471 >19.3 u 308 8274 834 >19.6 w1 687 8070 588 >19.5 m2 662 7865 607 >20.4 w2 614 7455 607 >20.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 2.21 in the direction of the burst (Schlegel et al. 1998).