Star Formation Law in Nearby Galaxies

Star formation governs the secular evolution of galaxies.  Within galaxies, we usually describe star formation in terms of an empirical "law" that relates the local star formation rate to local conditions such as molecular gas density.  While this model serves as a good first step, it breaks down beyond normal star-forming disk galaxies.  In this talk I will show how the EDGE-CALIFA survey of CO emission allows a new dissection of the star formation law using tools from the machine learning community.  This analysis illustrates the strong role of the old stellar population at quenching star formation on a local scale.  Unfortunately, the machine learning approach is empirical and lacks a clear connection to the underlying physics.  To understand the physical effects at work, I will show new results from the PHANGS survey, a large program with ALMA to map 74 nearby galaxies at high (<100pc) resolution.  One immediate result we see from the PHANGS data is that the dynamical state of molecular gas shows a near-balance between gravitational and kinetic energies over a huge range of physical conditions.  I will discuss the implications of this result and the next steps for investigation.

Speaker: Eric Rosolowsky, Univ. of Alberta