Cosmic-Ray Induced Diffuse Emissions from the Milky Way and Local Group Galaxies

TL;DR

This paper models the spectral energy distribution of cosmic-ray induced diffuse emissions across the electromagnetic spectrum in the Milky Way and nearby galaxies, aiding understanding of cosmic-ray impacts on galactic processes.

Contribution

It presents a comprehensive model of galaxy emissions from radio to gamma rays, including applications to the Magellanic Clouds and M31, based on recent work.

Findings

Successful modeling of the full spectral energy distribution from radio to gamma rays.

Application of models to the Magellanic Clouds and M31 with gamma-ray detections.

Insights into cosmic-ray interactions and their role in galaxy evolution.

Abstract

Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and galactic evolution. Diffuse emissions from radio to high-energy gamma rays (> 100 MeV) arising from various interactions between cosmic rays and the interstellar medium, interstellar radiation field, and magnetic field, are currently the best way to trace the intensities and spectra of cosmic rays in the Milky Way and other galaxies. In this contribution, I describe our recent work to model the full spectral energy distribution of galaxies like the Milky Way from radio to gamma-ray energies. The application to other galaxies, in particular the Magellanic Clouds and M31 that are detected in high-energy gamma-rays by the Fermi-LAT, is also discussed.