F. Marshall (GSFC), P. Brown (PSU), S. Immler (GSFC/USRA), and
G. Cusumano (IASF-Pa INAF) report on behalf of the Swift team:
The optical counterpart of the unusual GRB 060218
(Cusumano et al. (GCN 4775), Marshall et al. (GCN 4779))
is detected in all 6 of the Swift/UVOT broad-band filters
(V, B, U, UVW1, UVM2, UVW2). The filters collectively cover
the wavelength range from 180 to 560 nm. The light curves
for all the filters have similar shapes. The emission steadily
brightens by 1 to 2 magnitudes from the first detection about
150 s. after the burst trigger, peaks in a broad plateau
about 10 hours after the trigger, and then slowly declines for
at least the next 20 hours. Peak magnitudes
are 17.8, 17.7, 16.3, 16.2, 16.1, and 16.0 for the
V, B, U, UVW1, UVM2, and UWW2 filters respectively.
UVOT observations are continuing.