Probing large-scale magnetism with the Cosmic Microwave Background

TL;DR

This paper explores how primordial magnetic fields influence the cosmic microwave background's anisotropies, polarization, and potential circular polarization, integrating plasma physics, general relativity, and astrophysics.

Contribution

It critically analyzes the theoretical basis and recent advances in understanding large-scale magnetism's effects on the CMB.

Findings

Magnetic fields in the nano-Gauss range distort CMB anisotropies.

They can induce a unique B-mode polarization pattern.

Potential generation of frequency-dependent circular polarization (V-mode).

Abstract

Prior to photon decoupling magnetic random fields of comoving intensity in the nano-Gauss range distort the temperature and the polarization anisotropies of the microwave background, potentially induce a peculiar B-mode power spectrum and may even generate a frequency-dependent circularly polarized V-mode. We critically analyze the theoretical foundations and the recent achievements of an interesting trialogue involving plasma physics, general relativity and astrophysics.