Beyond CMB cosmic variance limits on reionization with the polarized SZ effect

TL;DR

This paper proposes using measurements of the polarized Sunyaev-Zel'dovich effect to reconstruct the reionization history of the universe, significantly improving constraints on optical depth beyond traditional cosmic variance limits.

Contribution

It introduces a novel method to utilize polarized SZ measurements for detailed reionization history reconstruction, surpassing existing cosmic variance constraints.

Findings

Quadrupole measurements up to redshift 3 can improve optical depth constraints.

The method can enhance reionization history understanding beyond CMB cosmic variance limits.

Potential for new cosmological insights from upcoming CMB surveys.

Abstract

Upcoming cosmic microwave background (CMB) surveys will soon make the first detection of the polarized Sunyaev-Zel'dovich effect, the linear polarization generated by the scattering of CMB photons on the free electrons present in collapsed objects. Measurement of this polarization along with knowledge of the electron density of the objects allows a determination of the quadrupolar temperature anisotropy of the CMB as viewed from the space-time location of the objects. Maps of these remote temperature quadrupoles have several cosmological applications. Here we propose a new application: reconstruction of the cosmological reionization history. We show that with quadrupole measurements out to redshift 3, constraints on the mean optical depth can be improved by an order of magnitude beyond the CMB cosmic variance limit.