The Cosmic Microwave Background and Its Polarization

TL;DR

This review summarizes the state-of-the-art in CMB polarization research, highlighting recent discoveries, observational constraints, challenges like foreground contamination, and future measurement prospects in cosmology.

Contribution

It provides a comprehensive overview connecting observational data to physical models of CMB polarization and discusses the implications for understanding cosmological parameters.

Findings

DASI discovery confirmed by WMAP

Significant foreground contamination at large scales

Current constraints on polarization parameters

Abstract

The DASI discovery of CMB polarization, confirmed by WMAP, has opened a new chapter in cosmology. Most of the useful information about inflationary gravitational waves and reionization is on large angular scales where Galactic foreground contamination is the worst. The goal of the present review is to provide the state-of-the-art of the CMB polarization from a practical point of view, connecting real-world data to physical models. We present the physics of this polarized phenomena and illustrate how it depends of various cosmological parameters for standard adiabatic models. We also present all observational constraints to date and discuss how much we have learned about polarized foregrounds so far from the CMB studies. Finally, we comment on future prospects for the measurement of CMB polarization.