Comparative study of the relationships between CO isotopic luminosities
  and infrared luminosity for the Galactic dense cores
  Combining the 12CO(1-0), 13CO(1-0), and C18O(1-0) data with IRAS four band
data, we here estimate the physical parameters such as size, viral mass, and CO
J=1-0 isotopic and infrared luminosities for 29 dense molecular clouds from two
published CO samples. We further analyze the various correlations between CO
J=1-0 isotopic luminosities and infrared luminosity (star formation rate, SFR)
and discuss the relationships between the molecular gas tracers and SFR. The
results show that 12CO(1-0), 13CO(1-0) and C18O(1-0) luminosities have tight
correlations with each other. CO J=1-0 isotopic luminosities and SFR show weak
correlations with lager scatter than the HCN-IR correlations of 47 dense cores
in the Galaxy and 65 external star-forming galaxies. This might be interpreted
as that both the SFR and star formation efficiency are mainly determined by the
molecular gas at high volume density rather than high column density.
