Grant: Discovery Grants Program - Individual

Galaxies are vast self-gravitating systems of planets, stars, gas, and dark matter, making them the basic building blocks of structure in the Universe. Therefore, understanding the formation and evolution of galaxies is crucial to discerning the history of the Universe and our place within it. While the Hubble telescope has provided us with a wealth of information about present-day galaxies, observing the initial stages of galaxy formation has been difficult. This paucity of information deprives us of a complete evolutionary picture of the cosmic structure formation process. These first galaxies formed within a billion years after the Big Bang, and they play an essential evolutionary role in bridging the gap between the smooth matter distribution at early times and the complex galaxies observed today. In addition, these primitive galaxies impact their surroundings by emitting high-energy radiation that causes a phase transition of the Universe's cold, neutral gas by heating and ionizing it. Therefore, answering several outstanding questions about this epoch is essential, such as when did these first galaxies form? What processes are responsible for regulating their properties? Which galaxies are responsible for driving reionization? And can we use these primitive galaxies to learn about the nature of dark matter and dark energy? Fortunately, the recent advent of instruments such as JWST has led to a flood of observational data that will usher the study of primitive galaxies into a new high-precision era. Therefore, theoretical and numerical models must achieve sufficient accuracy and physical fidelity to interpret these exciting new results meaningfully. The proposed research aims to establish novel numerical models that will efficiently leverage current and upcoming observations to constrain the physics of high redshift galaxy formation and evolution. The primary goal is to develop predictive galaxy formation models coupled with accurate radiation hydrodynamics to study reionization and structure formation within the first billion years after the Big Bang. The proposed research will tackle the multi-scale nature of these processes by coupling large-volume simulations designed to study the large-scale statistical properties of the universe with very high-resolution simulations that zoom-in on single galaxies, which are ideal for predicting their resolved properties. Even higher-resolution simulations will be used to improve the predictive power of the sub-resolution models used in the larger-scale simulations. This hierarchy of predictive numerical simulations and accurate observational forecasts promises important and transformative changes in our understanding of the primitive Universe, which will help us get closer to the goal of piecing together a complete evolutionary picture of the cosmic structure formation process.