  Optical and near-infrared observations of the Type Ic supernova (SN) 2004aw
are presented, obtained from day -3 to day +413 with respect to the B-band
maximum. The photometric evolution is characterised by a comparatively slow
post-maximum decline of the light curves. The peaks in redder bands are
significantly delayed relative to the bluer bands, the I-band maximum occurring
8.4 days later than that in B. With an absolute peak magnitude of -18.02 in the
V band the SN can be considered fairly bright, but not exceptional. This also
holds for the U through I bolometric light curve, where SN 2004aw has a
position intermediate between SNe 2002ap and 1998bw. Spectroscopically SN
2004aw provides a link between a normal Type Ic supernova like SN 1994I and the
group of broad-lined SNe Ic. The spectral evolution is rather slow, with a
spectrum at day +64 being still predominantly photospheric. The shape of the
nebular [O I] 6300,6364 line indicates a highly aspherical explosion. Helium
cannot be unambiguously identified in the spectra, even in the near-infrared.
Using an analytical description of the light curve peak we find that the total
mass of the ejecta in SN 2004aw is 3.5-8.0 M_Sun, significantly larger than in
SN 1994I, although not as large as in SN 1998bw. The same model suggests that
about 0.3 M_Sun of {56}Ni has been synthesised in the explosion. No connection
to a GRB can be firmly established.
