Abstract

Understanding how the physical properties of the ISM, star formation activities, and the effects of stellar feedback evolve across cosmic time is critical for establishing a coherent picture of galaxy formation and evolution. I will talk about results from the Feedback in Realistic Environments (FIRE) project, which is a library of cosmological zoom-in simulations with explicit treatment of the ISM, star formation, and feedback physics. At z>1, the ISM is mainly supported by turbulence driven by gas inflow, mergers, and stellar feedback. Star formation is highly bursty with strong feedback-driven outflows. Rotationally supported disks may form intermittently, but they are vulnerable to feedback. Milky Way-mass galaxies form a stable gas disk below z~1, when the SFR becomes nearly constant. I will talk about several consequences of the ‘bursty’ phase at early times: (1) the diversity of gas-phase metallicity gradients in z>0 galaxies, (2) the efficient formation of bound star clusters (progenitors of present-day globular clusters) at early times, and (3) the difficulty of fueling supermassive black hole seeds in the early universe. I will show that the early-time ‘bursty’ phase in the life of galaxies is not well understood. I will discuss what has converged and what has not yet converged with respect to variations of models and what observations in the coming years can be used to better understand galaxy formation physics.