Probing the epoch of reionization with the fossil record of nearby dwarf galaxies
Abstract
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.- Publication:
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HST Proposal
- Pub Date:
- June 2019
- Bibcode:
- 2019hst..prop15809W