Executive Summary : | The Universe entered the dark ages about half a million years after the Big Bang, as electrons recombined and the surface of last scattering was emitted. During this time, primordial density perturbations in neutral hydrogen evolved into dense structures, leading to the formation of first sources of light (stars and galaxies) that ended the dark ages and reionized the Universe. The development of the JWST, a space-based observatory, has initiated a new chapter in galaxy formation and reionization. Radio-astronomy surveys like the Murchison Widefield Array and the Square Kilometer Array provide a window into the epoch of reionization. To understand the process of reionization by Lyman-continuum photons emitted by infant galaxies in the early Universe, a rigorous theoretical and computational effort is needed. This project aims to develop models and simulations that enable us to understand the process of reionization by Lyman-continuum photons emitted by infant galaxies in the early Universe. The fossils of stars and galaxies that reionized the Universe might be inside the Milky Way at present. This search falls under the field of Galactic archaeology, where researchers use the GAIA satellite to build a comprehensive map of stars in the Milky Way and reconstruct the assembly history of the Milky Way. Using valuable data from GAIA and other surveys, the project aims to identify the fossil signatures of pre-reionization galaxies and stars by investigating the old and metal-poor stellar population in our Galaxy. |