Presentation #131.02 in the session “Star Formation on Small-scales”.
We investigate the extent to which mid-infrared spectra can be utilized to trace the star formation rate, molecular gas content, and gas depletion timescale of star-forming regions in galaxies. We show that pairing mid-infrared (MIR) emission lines from ionized neon with metallicity-dependent emission feature ratios results in a robust tracer of recent star-formation. We investigate the relation between H2 emission and molecular gas mass using high resolution MIR spectra from the Spitzer Infrared Nearby Galaxies Survey and CO J=(1-0) and (2-1) emission maps from several mm surveys. The rotational lines H2S(0-2) [i.e., 28.2μm H2S(0), 17.0μm H2S(1), and 12.3μm H2S(2)] are known to trace the warm fraction of molecular gas (approximately 100K - 1000K) and CO emission traces the column density of the cold fraction of H2 gas. We explore the potential of using MIR emission features to trace variations in the molecular gas star formation efficiency and discuss possible applications with future James Webb Space Telescope observations of distant galaxies.