GCN Circular 4785
F. Marshall (GSFC), S. Immler (GSFC/USRA) and G. Cusumano (IASF-Pa INAF) report on behalf of the Swift team: Continuing UVOT observations of the possible GRB 060218 show that the candidate optical afterglow reported by Cusumano et al. (GCN 4775) and Marshall et al. (GCN 4779) has brightened by a factor of about 5 in the 10 hours since the BAT trigger. Consequently, this source is unlikely to be the optical afterglow of a GRB. This brightening, the extended emission detected with BAT, and the possible BAT detection a month earlier (Barbier et al. GCN 4780) suggest that the UVOT source is the optical counterpart of a hard X-ray transient.