Speaker
Description
Large-scale cosmological simulations of galaxies like IllustrisTNG have been enormously useful at providing quantitative insights on galaxy evolution, especially after the end of Reionization. However, their limited numerical resolution and, crucially, their crude implementations of the physics of star formation, of stellar feedback, of cold gas and of the interstellar medium makes them less applicable to provide theoretical guidance onto how galaxies form and evolve in the first billion year of the Universe history. In this talk, I will present our efforts to simulate galaxies in the full cosmological context with a new model that includes multi-phase gas with non-equilibrium primordial chemistry down to 10 K, explicit energy injections from exploding supernova, stellar ionizing and non ionizing radiation and hence photoionization feedback and photoelectric heating, and star formation based on a Jeans-instability criterion and constant efficiency per free-fall time. This model is designed for ultra-high resolution simulations, reaching mass scales of actual individual stars. We will present first results from simulated galaxies at 20-200 solar-mass resolution (~1000 x better than TNG50) and with sub-parsec spatial resolution of the gas. I will focus on scientific results at z>5-6 and on what these simulations are telling us about the formation of very dense and very compact stellar systems in the early Universe and on how star formation may proceed across a variety of galactic environments.
