Colloquium on 9 July 2015
Equilibrium Model for Galaxy Evolution


Title: Equilibrium Model for Galaxy Evolution
Speaker: Sourav Mitra (CET Fellow, UWC)
Date: Thursday, 9 July 2015
Time: 11:00 - 12:00
Venue: SAAO Auditorium


Galaxies strongly self-regulate their growth via energetic feedback from stars, supernovae, and black holes, but these processes are among the least understood aspects of galaxy formation theory. We present an analytic galaxy evolution model that directly constrains such feedback processes from observed galaxy scaling relations. The equilibrium model, which is broadly valid for star-forming central galaxies that dominate cosmic star formation, is based on the ansatz that galaxies live in a slowly-evolving equilibrium between inflows, outflows, and star formation. Using a Bayesian Monte Carlo Markov chain approach, we constrain our model to match observed galaxy scaling relations between stellar mass and halo mass, star formation rate, and metallicity across cosmic time. We will show that this simple analytic framework captures the basic physical processes required to model the mean evolution of stars and metals in galaxies, despite not incorporating many canonical ingredients of galaxy formation models such as merging or disk formation.

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