Cosmological probes of helium reionization

Understand

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.