The Star Formation Rate-Dense Gas Relation in the Nuclei of Nearby Galaxies

Abstract

We investigate the relationship between the star formation rate (SFR) and dense molecular gas mass in the nuclei of galaxies. To do this, we utilize the observed 850 mu m luminosity as a proxy for the infrared luminosity (L-IR) and SFR, and we correlate this with the observed CO(J = 3-2) luminosity. We find tentative evidence that the L-IR-CO (J = 3-2) index is similar to the Kennicutt-Schmidt (KS) index (N approximate to 1.5) in the central similar to 1.7 kpc of galaxies, and it flattens to a roughly linear index when including emission from the entire galaxy. This result may imply that the volumetric Schmidt relation is the underlying driver behind the observed SFR-dense gas correlations, and it provides tentative confirmation for recent numerical models. While the data exclude the possibility of a constant L-IR-CO(J = 3-2) index for both galaxy nuclei and global measurements at the similar to 80% confidence level, the considerable error bars cannot preclude alternative interpretations.