Comparative study of the relationships between CO isotopic luminosities and infrared luminosity for the Galactic dense cores

TL;DR

This study investigates the relationships between CO isotopic luminosities and infrared luminosity in Galactic dense cores, revealing that molecular gas at high volume density influences star formation more than high column density.

Contribution

It provides a comparative analysis of CO isotopic and infrared luminosities, highlighting their correlations and implications for star formation processes in dense molecular clouds.

Findings

CO isotopic luminosities are tightly correlated with each other.

Weak correlation between CO isotopic luminosities and SFR compared to HCN-IR correlations.

Star formation efficiency is mainly influenced by high volume density molecular gas.

Abstract

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.