Cosmic Reionization: uncertainties, modeling, and how to extract all information from future surveys

Abstract: Reionization marks the last major global transition of the Universe, during which the birth of the first luminous cosmic structures gradually reionized the Inter-galactic medium. Several observational efforts are devoted to detecting and constraining reionization on small and large scales. These include, for instance, the recently launched NASA’s James Webb Space Telescope (JWST), the Euclid, the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx), the Nancy Grace Roman Space Telescope (Roman), and many more. Due to the unprecedented sensitivity and large field of view, future surveys will enable detecting the majority of high redshift sources (quasars and galaxies) responsible for reionization on extremely large scales (> Gpc). Hence, a new generation of theoretical models is required to maximize the scientific return of future surveys. In this talk, I will discuss the key questions about the nature of reionization and the various different probes. I will also discuss uncertainties in our current theoretical models and the progress that has been made to answering these questions. In the end, I will present some of my own contributions to improve modeling reionization using a combination of simulations and machine learning methods.