Nonthermal particles and photons in starburst regions and superbubbles

TL;DR

This paper reviews how energetic particles and nonthermal emissions in starburst regions and superbubbles influence galactic environments, focusing on particle acceleration, magnetic field amplification, and their observational signatures.

Contribution

It provides a comprehensive review of observational data and models on nonthermal emissions, particle acceleration, and magnetic field amplification in starburst regions and superbubbles.

Findings

Identification of efficient particle acceleration mechanisms.

Discussion of magnetic field amplification processes.

Review of potential galactic PeVatrons and their role in cosmic ray production.

Abstract

Starforming factories in galaxies produce compact clusters and loose associations of young massive stars. Fast radiation-driven winds and supernovae input their huge kinetic power into the interstellar medium in the form of highly supersonic and superalfvenic outflows. Apart from gas heating, collisionless relaxation of fast plasma outflows results in fluctuating magnetic fields and energetic particles. The energetic particles comprise a long-lived component which may contain a sizeable fraction of the kinetic energy released by the winds and supernova ejecta and thus modify the magnetohydrodynamic flows in the systems. We present a concise review of observational data and models of nonthermal emission from starburst galaxies, superbubbles, and compact clusters of massive stars. Efficient mechanisms of particle acceleration and amplification of fluctuating magnetic fields with a wide dynamical range in starburst regions are discussed. Sources of cosmic rays, neutrinos and multi-wavelength nonthermal emission associated with starburst regions including potential galactic "PeVatrons" are reviewed in the global galactic ecology context.