GCN Circular 34643
S. R. Oates (Lancaster U. ) and M. J. Moss (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 230906A 93 ks after IPN-detection (Kozyrev et al., GCN Circ 34637). No optical afterglow consistent with the XRT position (Beardmore et al., GCN Circulars 34639), 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 93297 106009 4648 >22.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.021 in the direction of the burst (Schlegel et al. 1998).