  We present the first results of the BIMA Survey of Nearby Galaxies (BIMA
SONG), an imaging survey of the CO J=(1-0) emission in 44 nearby spiral
galaxies at a typical resolution of 6". BIMA SONG differs from previous
high-resolution CO surveys in that: (1) CO brightness was not an explicit
selection criterion; (2) a larger area (200" diameter for most galaxies) of
each galaxy was imaged; and (3) fully-sampled single-dish CO data (55"
resolution) were obtained for over half of the sample galaxies, so all of the
CO flux is imaged in these galaxies. The radial distribution of stellar light
in galactic disks is generally characterized as an exponential. It is,
therefore, of interest to investigate whether the molecular gas, which is the
star-forming medium, has a similar distribution. Though our low-resolution
single-dish radial profiles of CO emission can be described by simple
exponentials, this is not true for the emission at our full 6" resolution. The
scale lengths of the CO disks are correlated with the scale lengths of the
stellar disks with a mean ratio of the scale lengths of about one. We also find
that:(1) there is also a weak correlation between the ratio of K-band to CO
luminosity and Hubble type; (2) in half of the galaxies presented here, CO
emission does not peak at the location of the stellar nucleus; (3) averaged
over the inner kiloparsec, the CO emission in one-half of the galaxies exhibits
an excess over that expected from an exponential disk which is similar to the
excess in stellar light caused by the bulge stars; and (4) this excess CO
emission may be due to an increase in the total molecular gas content in the
bulge region, or alternatively, to an increase in the CO emissivity caused by
the increased pressure of the bulge region.
