initial submission -395392600 Assigned ID: 3608 ----- Attempting Submission 1 (Fri Mar 25 21:54:33 GMT 2022) ----- We propose to implement Population III star formation into the FIRE simulation project to (i) understand its effect on dwarf galaxies across cosmic history and (ii) publicly provide a physically-motivated prescription for the initial metallicity adopted in general cosmological simulations without direct Population III physics. A primary goal of HST, and eventually JWST, is to understand the formation and fate of the first galaxies and the stars they are composed of. This includes Population III (metal-free) stars, which have been studied extensively in high-redshift simulations. However, connections between Population III stars and the low- redshift Universe are crucial to consider, as metal enrichment from the first stars might be the origin of one of the few glaring mismatches between observations and simulations of ultra-faint dwarf galaxies: observed dwarf galaxies all have [Fe/H] > -3, whereas simulated ultra-faint dwarfs often form with the (much lower) lowest metallicity possible in a simulation (which is put in by hand). We will perform cosmological simulations of ultra-faint dwarf galaxies to trace the effects of the first stars from initial conditions to redshift z=0. With the results, we will directly study the impact of Population III star formation on dwarf galaxy properties as a function of time. We will investigate how metals from the first stars enrich the IGM of dwarf galaxies and how this is reflected in subsequent generations of star formation. This program will enable more detailed comparisons between modern galaxy formation simulations that include all generations of star formation and forefront HST science in both the near field and in deep fields. Dr. Anna Schauer (PI) is a well-known expert in the field of numerical studies of Population III star formation and its effects on high-redshift galaxies. She has worked extensively on Population III star physics in numerical simulations and on running and analyzing those simulations. Prof. Mike Boylan-Kolchin (CoPI) has broad expertise in cosmological simulations, connections between near-field and deep-field observations, and dwarf galaxies as cosmological probes. He is one of the PIs of the FIRE collaboration and has worked extensively with FIRE simulations. Prof. Volker Bromm (CoI) is a leading expert on Population III stars, high-redshift galaxy formation, and numerical simulations. Much of our current understanding of Population III star formation has its origins in his work. Galaxies Stellar Populations and the Interstellar Medium 0 Regular false false false true false false SUPPORTED