Cosmological Magnetic Fields

TL;DR

This paper reviews the observational evidence, generation mechanisms, and potential CMB imprints of large-scale cosmic magnetic fields, exploring their primordial origins and implications for early universe physics.

Contribution

It provides a comprehensive overview of the current understanding and observational constraints on primordial magnetic fields and their signatures in the CMB.

Findings

Observational evidence supports large-scale cosmic magnetic fields.

Generation mechanisms for primordial magnetic fields are discussed.

CMB observations can constrain properties of early universe magnetic fields.

Abstract

Magnetic fields are observed on nearly all scales in the universe, from stars and galaxies upto galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin in the very early universe. A magnetic dynamo amplifying an initial seed magnetic field could explain the present day strength of the galactic magnetic field. However, it is still an open problem how and when this initial magnetic field was created. Observations of the cosmic microwave background (CMB) provide a window to the early universe and might therefore be able to tell us whether cosmic magnetic fields are of primordial, cosmological origin and at the same time constrain its parameters. We will give an overview of the observational evidence of large scale magnetic fields, describe generation mechanisms of primordial magnetic fields and possible imprints in the CMB.