TITLE: GCN CIRCULAR NUMBER: 23819 SUBJECT: GRB 190129B: Swift/UVOT Upper Limits DATE: 19/01/30 19:55:48 GMT FROM: Paul Kuin at MSSL S.W.K. Emery (UCL-MSSL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 190129B 44980 s after the IPN-detected burst (Hurley et al. GCN Circ. 23808). No optical afterglow consistent with either the XRT position of the uncatalogued X-ray source, source 1 (LaPorte et al. GCN Circ. 23813) or the position of the GROND candidate (Bolmer et al. GCN Circ. 23814) 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 exposures at the position of source 1 are: Filter T_start(s) T_stop(s) Exp(s) Mag u 44980 60425 208 > 20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).