Magnetized CMB anisotropies

Abstract

Possible effects of large-scale magnetic fields on the Cosmic Microwave Background (CMB) are reviewed. Depending on the specific branch of the spectrum of plasma excitations, magnetic fields are treated either within a two-fluid plasma description or within an effective (one-fluid) approach. The uniform field approximation is contrasted with the fully inhomogeneous field approximation. It is argued that the interplay between CMB physics and large-scale magnetic fields will represent a rather interesting cross-disciplinary arena along the next few years.Comment: 61 pages, 5 figures, references added, to appear as Topical Review in Classical and Quantum Gravit