Cosmic-ray leptons, magnetic fields and interstellar synchrotron emission

TL;DR

This paper advances modeling of Galactic synchrotron emission by incorporating polarization, absorption, and free-free effects, using radio surveys to constrain cosmic-ray electrons, magnetic fields, and propagation models, aiding gamma-ray and Planck studies.

Contribution

It introduces updated GALPROP models with enhanced features and applies them to multi-frequency radio data to better understand cosmic-ray electrons and magnetic fields in the Galaxy.

Findings

Constraints on low-energy cosmic-ray electron spectrum

Refined models of Galactic magnetic fields

Improved understanding of cosmic-ray propagation

Abstract

Interstellar synchrotron emission depends on Galactic magnetic fields and on cosmic-ray leptons. Observations of radio emission are an important tool for studying cosmic-ray propagation models and interstellar electron spectrum and distribution in the Galaxy. We present the latest developments in our modeling of Galactic synchrotron emission with the GALPROP code, including polarization, absorption, and free-free emission. Using surveys over a wide range of radio frequencies and polarization measurements, we derive constraints on the low-energy interstellar cosmic-ray electron spectrum, magnetic fields and cosmic-ray propagation models. This work is of interest for studies of interstellar gamma-ray emission with Fermi-LAT, and synchrotron for the Planck mission.