GCN Circular 34399
Paul Kuin (MSSL/UCL) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 230812 25418 s after the GBM trigger (Roberts et al., GCN Circ. 34391). The Fermi LAT also detected the trigger (Scotton et al, GCN Circ. 34392). An candidate optical counterpart was reported (Zheng & Filippenko, GCN Circ. 34395; Lipunov et al., GCN Circ 34396; Salgundi et al., GCN Circ. 34397) near the reported XRT candidate (Kennea, GCN Circ. 34393, Page, GCN Circ. 34394). A source consistent with the XRT position is detected in the UVOT exposures. Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 25418 31151 390 20.48 +/- 0.18 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.024 in the direction of the burst (Schlegel et al. 1998).