TITLE: GCN CIRCULAR NUMBER: 23367 SUBJECT: GRB 181022A: Swift/UVOT Upper Limits DATE: 18/10/23 03:30:07 GMT FROM: Sam LaPorte at PSU GRB 181022A: Swift/UVOT Upper Limits S. J. LaPorte (PSU) and F. E. Marshall (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 181022A 78 s after the BAT trigger (Marshall et al., GCN Circ. 23364). No optical afterglow consistent with the XRT position (Marshall et al. GCN Circ. 23364) 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 u_FC 98 347 246 >20.5 v 78 4922 288 >19.8 u 98 5429 503 >20.4 w1 661 5332 274 >20.1 m2 4927 5127 197 >20.2 w2 356 4717 442 >20.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).