Magnetic fields in the Large-Scale Structure of the Universe

TL;DR

This paper reviews the current understanding of magnetic fields in the large-scale structure of the universe, focusing on their origins, evolution, and implications, especially outside galaxy clusters where observations are limited.

Contribution

It synthesizes recent developments and proposes mechanisms for the generation and amplification of intergalactic magnetic fields in the context of cosmic structure formation.

Findings

Seed fields likely created in the early universe.

Turbulent flows amplify magnetic fields during structure formation.

Intergalactic magnetic fields have significant cosmological implications.

Abstract

Magnetic fields appear to be ubiquitous in astrophysical environments. Their existence in the intracluster medium is established through observations of synchrotron emission and Faraday rotation. On the other hand, the nature of magnetic fields outside of clusters, where observations are scarce and controversial, remains largely unknown. In this chapter, we review recent developments in our understanding of the nature and origin of intergalactic magnetic fields, and in particular, intercluster fields. A plausible scenario for the origin of galactic and intergalactic magnetic fields is for seed fields, created in the early universe, to be amplified by turbulent flows induced during the formation of the large scale structure. We present several mechanisms for the generation of seed fields both before and after recombination. We then discuss the evolution and role of magnetic fields during the formation of the first starts. We describe the turbulent amplification of seed fields during the formation of large scale structure and the nature of the magnetic fields that arise. Finally, we discuss implications of intergalactic magnetic fields.