Cosmological probes of helium reionization

TL;DR

This paper proposes a method to study the epoch of helium reionization (z=2-4) by combining CMB data with infrared background and high-redshift galaxy observations, enabling insights into early galaxy and black hole formation.

Contribution

It introduces a novel joint analysis technique using kinetic Sunyaev Zel'dovich tomography to probe helium reionization on the light cone with upcoming observational data.

Findings

Expected detection significance of 8-10 sigma with future data sets.

Demonstrates potential to understand galaxy formation and quasar activity during reionization.

Highlights the importance of combined CMB and infrared galaxy observations.

Abstract

Joint analysis of CMB and large-scale structure at high redshifts provide new and unique windows into unexplored epochs of early structure formation. Here, we demonstrate how cosmic infrared background and high-redshift galaxies can be jointly analysed with CMB to probe the epoch of helium reionization ($2<z<4$) on the light cone using kinetic Sunyaev Zel'dovich tomography. Characterising this epoch has great potential significance for understanding astrophysics of galaxy formation, quasar activity and formation of the super-massive black holes. We find a detection at $8-10\sigma$ can be expected from combinations of data from CCAT-prime, Vera Rubin Observatory and CMB-S4 in the upcoming years.