Cross-correlation studies with future CMB experiments.

The observation of the Cosmic Microwave Background (CMB) is a powerful probe to unravel many mysteries of the late-time Universe. I will review present constraints on the parameters related to the reionization process and galaxy clusters. In the near future, we will have access to low noise and high sensitive CMB datasets and hence, the question arises of what new information we can get about the detailed physics of the reionization process and galaxy clusters. We propose a new reionization probe that uses   CMB observations: the cross-correlation between fluctuations in the CMB  optical depth which probes the integrated electron density, and the Compton y-map which probes the integrated electron pressure. I will discuss how this cross-correlation technique is used to put the first constraints on the temperature and size of the ionized bubbles from the Planck data. On the other hand, I will explain how different cross-correlation studies between CMB and galaxy surveys, can be used to constraint the density and pressure profile of galaxy clusters. I will conclude by discussing the prospects of these studies by upcoming CMB experiments, like Simons Observatory, CMB-S4, and CCAT-prime.