Radio continuum, co, and thermal infrared emission in nearby star-forming galaxies

Abstract

The correlation between far-infrared and radio emission in galaxies is remarkably strong considering the very different emission mechanisms which are thought to be responsible for the two. We have examined this correlation in the LMC on scales ranging from 40 pc to 4 kpc, finding that the FIR-radio correlation remains extremely tight down to <100 pc, whereas correlations of either FIR or radio with Hi or CO degrade considerably below 1 kpc. However, in nearby spiral galaxies the mid-infrared (MIR) and radio emission begin to decor-relate even on scales of <2 kpc. The difference in behaviour from the LMC may be due to the larger fraction of synchrotron flux in more massive galaxies.