Diffuse Synchrotron Emission from Galactic Cosmic Ray Electrons

TL;DR

This paper models Galactic synchrotron emission using 3D cosmic ray electron distributions from the DRAGON code, improving understanding of Galactic magnetic fields and aiding CMB studies.

Contribution

It introduces the first use of 3D GCRE models with spiral arm structure to accurately simulate synchrotron emission in the Galaxy.

Findings

Enhanced modeling of SDR with realistic spiral arm structures.

Improved constraints on Galactic magnetic field properties.

Better foreground models for CMB and extragalactic measurements.

Abstract

Synchrotron diffuse radiation (SDR) emission is one of the major Galactic components, in the 100 MHz up to 100 GHz frequency range. Its spectrum and sky map provide valuable measure of the galactic cosmic ray electrons (GCRE) in the relevant energy range, as well as of the strength and structure of the Galactic magnetic fields (GMF), both regular and random ones. This emission is an astrophysical sky foreground for the study of the Cosmic Microwave Background (CMB), and the extragalactic microwave measurements, and it needs to be modelled as better as possible. In this regard, in order to get an accurate description of the SDR in the Galaxy, we use - for the first time in this context - 3-dimensional GCRE models obtained by running the DRAGON code. This allows us to account for a realistic spiral arm pattern of the source distribution, demanded to get a self-consistent treatment of all relevant energy losses influencing the final synchrotron spectrum.