Studying Star Formation Using High-Resolution Numerical Simulations of Galaxy FormationPublic Deposited
Hydrodynamic simulations of galaxy formation have proven to be incredibly useful tools in understanding the nature of star formation. Many modern simulations have identified the importance of and implemented new and powerful schemes for including the stellar feedback processes that regulate star formation, such as the FIRE simulations. The FIRE galaxy formation simulations use a self consistent star formation scheme that requires gas be gravitationally bound, sufficiently dense, and sufficiently cold. This results in galaxies with a realistic population of stars with spatial distributions, ages, ambient properties, and that match the observationally-inferred star formation histories of galaxies. Subsequently, these stars launch realistic populations of supernovae with physical clustering in time and space without relying on any ad hoc scheme to account for this critical effect in generating additional momentum from expanding supernova remnants. Using these simulated galaxies, we study how the star formation rate evolves with time and eventually self-regulates as the weight of the star-forming material is balanced with the turbulent and thermal pressure support generated by feedback processes. We find that when these pressures are out of balance star formation can take on a “bursty” character as the system wildly overshoots the equilibrium state. Eventually however the galaxy “settles down,” falling onto the observed Kennicutt-Schmidt star formation relation after many billions of years of evolution. Future studies and simulations will be necessary to understand by what mechanism galaxies transition from the bursty, and out of equilibrium, state to their more time-steady counterpart.
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