Resolved Giant Molecular Clouds in Nearby Spiral Galaxies: Insights from
  the CANON CO (1-0) Survey
  We resolve 182 individual giant molecular clouds (GMCs) larger than 2.5
$\times$ 10$^{5}$ \Msun in the inner disks of five large nearby spiral galaxies
(NGC 2403, NGC 3031, NGC 4736, NGC 4826, and NGC 6946) to create the largest
such sample of extragalactic GMCs within galaxies analogous to the Milky Way.
Using a conservatively chosen sample of GMCs most likely to adhere to the
virial assumption, we measure cloud sizes, velocity dispersions, and $^{12}$CO
(J=1-0) luminosities and calculate cloud virial masses. The average conversion
factor from CO flux to H$_{2}$ mass (or \xcons) for each galaxy is 1-2
\xcounits, all within a factor of two of the Milky Way disk value ($\sim$2
\xcounits). We find GMCs to be generally consistent within our errors between
the galaxies and with Milky Way disk GMCs; the intrinsic scatter between clouds
is of order a factor of two. Consistent with previous studies in the Local
Group, we find a linear relationship between cloud virial mass and CO
luminosity, supporting the assumption that the clouds in this GMC sample are
gravitationally bound. We do not detect a significant population of GMCs with
elevated velocity dispersions for their sizes, as has been detected in the
Galactic center. Though the range of metallicities probed in this study is
narrow, the average conversion factors of these galaxies will serve to anchor
the high metallicity end of metallicity-\xco trends measured using conversion
factors in resolved clouds; this has been previously possible primarily with
Milky Way measurements.
