Unveiling the astrophysics of reionization in the post-reionization era
Date:
Cosmic reionization is the last major phase transition that our Universe goes through. In this milestone, the intergalactic medium transitions from primarily neutral, dark, and cold into mainly ionized, luminous, and warm. However, as exciting as the reionization process surely was, many aspects remain unknown, e.g. what are the sources of the ionizing photons? what is the timeline of reionization? Upcoming telescopes (e.g. JWST and HERA) will help to directly probe cosmic reionization. Nonetheless, interpretation of said measurements will strongly rely on modeling the surroundings of luminous objects (JWST) or on foreground removal (21 cm). In this talk, I will describe a promising novel method to constrain reionization through its impact in the post-reionization intergalactic medium. I will focus on the ability of the Lyman-alpha forest (using DESI) to unveil the astrophysics of reionization in the first part of my talk. In the second part, I will describe how we can further exploit this new methodology through cross-correlations of different cosmological probes of the post-reionization era. Furthermore, I will showcase the potential of this new methodology to constrain the nature of dark matter via its exquisite small-scale sensitivity.