Physics & Astronomy Chris Faesi, UMass: “The Forest AND the Trees: Bridging the Multi-Scale Physics of Star Formation”

The conversion of interstellar gas into stars provides the energy, momentum and chemical enrichment that help drive the evolution of galaxies across cosmic time. Observational limitations have previously made it difficult to obtain a comprehensive understanding of the star formation process (and its role on environment) due to the large dynamic range in scales over which it is relevant. However, pioneering new observational facilities are now moving the field from case studies to big data, enabling measurements across statistically significant samples of galaxies at very high resolution. This allows us for the first time to directly investigate how the small-scale (< 100 pc) physics of star formation couples to large-scale (1-10 kpc) galactic dynamics and environment.

In this presentation, I will highlight recent and current progress toward a more complete picture of star formation in the local Universe. I will show how new population synthesis models for young stellar populations can bridge the gap from Milky Way to extragalactic star formation studies. I will also present the results of the first molecular cloud-scale study of molecular clouds beyond the Local Group of galaxies. Finally, I will review some first results from two large observational campaigns through which we are tracking molecular gas and young stars at the cloud scale across dozens of nearby galaxies. This includes the systematic investigation of important physical quantities including gas conversion efficiency, molecular cloud densities and dynamics, and star formation timescales across multiple galactic environments.