Cosmic Magnetism

TL;DR

Cosmic magnetism is fundamental across all astrophysical scales, involving questions about their origins, evolution, and impact, with diverse observational and theoretical approaches needed to advance understanding.

Contribution

This paper reviews key scientific questions and discusses observational and theoretical opportunities in the study of cosmic magnetic fields.

Findings

Magnetic fields influence all astrophysical processes across scales.

Observations require multi-wavelength data from radio to gamma-ray.

Canada plays a leading role in global cosmic magnetism research.

Abstract

Magnetic fields are involved in every astrophysical process on every scale: from planetary and stellar interiors to neutron stars, stellar wind bubbles and supernova remnants; from the interstellar medium in galactic disks, nuclei, spiral arms and halos to the intracluster and intergalactic media. They are involved in essentially every particle acceleration process and are thus fundamental to non-thermal physics in the Universe. Key questions include the origin of magnetic fields, their evolution over cosmic time, the amplification and decay processes that modify their strength, and their impact on other processes such as star formation and galaxy evolution. Astrophysical plasmas provide a unique laboratory for testing magnetic dynamo theory. The study of magnetic fields requires observations that span the wavelength range from radio through infrared, optical, UV, X-ray, and gamma-ray. Canada has an extremely strong record of research in cosmic magnetism, and has a significant leadership role in several ongoing and upcoming global programs. This white paper will review the science questions to be addressed in the study of cosmic magnetic fields and will describe the observational and theoretical opportunities and challenges afforded by the telescopes and modelling capabilities of today and tomorrow.