0 Assigned ID: 260 ----- Attempting Submission 1 (Thu Apr 04 20:14:41 GMT 2019) ----- A primary goal of HST and eventually JWST is to understand the formation of the first galaxies and their role in driving the epoch of reionization at z ~ 7. However, consensus models of reionization suggest that the bulk of galaxies that drove reionization may be below HST and even JWST's direct detection thresholds at z ~ 7. An alternative "near-far" approach has emerged: to use the stellar fossil record of dwarf galaxies in the Local Group to probe the faint galaxy population and UV luminosity function at z ~ 7. In this Legacy Theory program, we propose to rigorously test and characterize how accurately HST near-field observations of the star-formation histories (SFHs) of Local Group (LG) dwarf galaxies can measure the faint end of the galaxy UV luminosity function at z ~ 7. We will use state-of-the-art cosmological zoom-in baryonic simulations of LG-like systems together with large-volumes simulations of galaxy populations at z ~ 7. We will quantify how accurately the histories of surviving LG dwarf galaxies at z = 0 reflect the overall galaxy populations at z ~ 7. Furthermore, we will create new tools for generating synthetic HST and JWST observations of these simulated dwarf galaxies, to quantify how accurately the SFHs from measured stellar populations in nearby dwarfs can infer their star formation rates and UV luminosities at z ~ 7. Finally, we will publicly release these synthetic observations and simulation data, to help leverage existing HST data and guide upcoming JWST observations. These public data products will provide testing grounds and calibration tools for any analysis of resolved stellar populations in nearby dwarf galaxies. This Legacy Theory program will bring together experts in both simulations and observations of dwarf galaxies in the Local Group, high-redshift galaxy populations, and connections between them. All team members are part of the FIRE simulation collaboration (except Prof. Dan Weisz and Dr. Erik Tollerud, who are primarily observers). PI Prof. Andrew Wetzel is an expert in cosmological simulations and is a developer of the Gizmo simulation code, FIRE physics model, and the Ananke code for generating synthetic observations from FIRE simulations; he leads the Latte suite of FIRE simulations of Milky Way-mass galaxies that we will use. Prof. Robyn Sanderson is an expert in statistical modeling of stellar populations in galaxies and is the lead developer of the Ananke code that we will use and further develop. Dr. Sarah Loebman is an expert in simulation analysis, data management, generating synthetic observations from simulations, survey-to-simulation comparisons, and is a co-developer of Ananke. Dr. Shea Garrison-Kimmel is an expert in cosmological simulations and leads the ELVIS on FIRE suite of Local Group-like systems that we will use. Dr. Xiangcheng Ma is an expert in cosmological simulations and leads the High-z suite of FIRE simulations that we will use. Dr. Andrew Graus is an expert in analyzing dwarf galaxies and their star-formation histories in cosmological simulations and comparing against observations. Prof. Dan Weisz and Dr. Erik Tollerud are experts in HST-based observations of resolved stellar populations in nearby dwarf galaxies and have developed extensive tools for measuring stellar populations and star-formation histories. Profs. Mike Boylan-Kolchin and James Bullock are experts in cosmological simulations and have developed models for the near-far connection of using stellar population of nearby dwarf galaxies to learn about the early Universe. Galaxies and the IGM Stellar Populations 0 Legacy false false false true false SUPPORTED