Unlocking the Early History of Galaxy Formation

Surveys of distant galaxies have challenged our understanding of the early phases of star and galaxy formation. These galaxies are brighter and more abundant than previously expected. Detailed studies have found further surprises: growing black holes, runaway star formation, quenched star formation, and even unusual stellar populations. A researcher at the University of California, Los Angeles, will develop computational tools and models that can help explain these surprises in a rigorous way. As part of the project, research tutorials for local high school and undergraduate students will be developed alongside outreach tools for small planetariums. The materials will focus on cutting-edge investigations of early galaxies and the Cosmic Dawn. The goal of project is to improve the physical modeling of galaxies in the early universe in several ways. First, an easily parameterized analytic model of the “burstiness” seen at early times will be developed. It will include an exploration of how the burstiness affects the chemical evolution of these galaxies. The framework will incorporate accreting black holes to constrain the processes governing the origin and growth of the early galaxies. In parallel, a new inference pipeline that can robustly compare observations to theoretical models will be built to stringently test the models. This is an important contribution, as most existing software is calibrated to galaxies at later times and cannot be directly compared to theoretical models. Using a Bayesian hierarchical approach, the novel inference framework will compare the data on an object-by-object basis. The resulting framework will directly compare a fast, flexible set of galaxy models to the data to constrain the key parameters of galaxy formation. The new inference pipeline will be released publicly to maximize the science return of observations and plan to for future surveys. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.