Searching for Simplicity in the High-Redshift Universe

Kristian Finlator

February 21, 2012

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Abstract: The study of galaxy evolution across cosmic time is maturing rapidly owing to the breathtaking pace of observational advances. The ongoing study of galaxies both as cosmological probes and as star formation laboratories motivate efforts to incorporate the diverse array of available observational clues into a minimal but comprehensive theoretical model. In this talk, I will describe recent insights from statistical comparisons between cosmological hydrodynamic simulations and observations. I will show that the observed abundance, colors, and metallicities of single- and multi-epoch galaxy samples are consistent with models in which the steady accretion of cold gas inflows drives the smooth star formation histories of bright galaxies. I will discuss theoretical insight into evidence for extreme high-redshift environments such as submillimeter galaxies and metal-free stellar populations. Finally, I will discuss early results on the coupling between galaxies and the intergalactic medium from radiation hydrodynamic simulations of the cosmic dark ages. Numerical models clearly support the idea that star formation in faint but metal-enriched galaxies drove reionization, but many questions regarding the dominant feedback processes remain unclear. These questions inform the ways in which observers will use next-generation facilities such as ALMA and JWST to decipher the very first stages of galaxy formation.