Cosmic Reionization: What can future CMB experiments tell us?

Cosmic reionization is an important event in the timeline of our universe as the universe transitioned from an almost completely neutral to an ionized state. The study of reionization is very important because the process is directly linked with the formation of the first cosmic structures and it affects their subsequent evolution. But there are limited observational constraints on the redshift, source and morphology of reionization. I'll first give a general view of Cosmic Microwave Background (CMB) polarization and I'll show how the reionization process makes it's unique signature on CMB power spectra. Afterwards I'll address the uncertainties in astrophysical modelling of reionization sources and observational constraints of reionization given by Planck satellite. We implement a procedure of extraction of the patchy reionization signal analogue to the one exploited for CMB lensing, and evaluate the signal to noise ratio for the future Stage IV (S4) CMB experiment. I'll talk about the detectability of signal from patchy reionization in view of the future high accuracy polarization measurements of the CMB like LiteBIRD, CMB S4, Simons Observatory and others.