TITLE: GCN CIRCULAR NUMBER: 26892 SUBJECT: GRB 200125A: Swift/UVOT Upper Limits DATE: 20/01/27 01:22:25 GMT FROM: Kira Simpson at PSU GRB 200125A: Swift/UVOT Upper Limits K. K. Simpson (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200125A 179 s after the BAT trigger (Lien et al., GCN Circ. 26876). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 26878) 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 179 329 147 >20.4 white 179 4176 344 >21.1 v 4387 4586 197 >18.4 b 3771 3971 197 >19.9 u 337 414 75 >18.9 w1 4796 4835 38 >18.6 m2 4591 4791 197 >19.3 w2 4182 4382 197 >20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.08 in the direction of the burst (Schlegel et al. 1998).