Carnegie Mellon University

Astro Seminar

A Big-picture Theoretical View on the Evolution of Star-forming Galaxies

In the field of galaxy evolution stellar feedback reigns supreme, evoked for everything from driving turbulence and regulating star formation to suppressing the stellar and baryonic mass of galaxies to fit constraints from abundance matching. Nonetheless, order-of-magnitude uncertainties remain in the rate at which feedback launches mass in galactic winds, and models based on stellar feedback tend to fall short of explaining both the high velocity dispersions of massive star-forming galaxies at z~2 and the low star formation rates of dwarfs. Using simple toy models, a new radially-resolved semi-analytic model, and idealized AMR simulations of isolated galaxies, I will discuss other physical mechanisms that may be at play. Turbulence and radial transport of gas and metals driven by Toomre gravitational instability, small-scale mixing of supernova ejecta, and interactions between cold accreting gas and the galaxy's hot halo all have the potential to substantially reduce stellar feedback's dominant role in our view of galaxy evolution.