An Alternative Approach for Constraining the Galactic Magnetic Field and the Interstellar Radiation Field

TL;DR

This paper explores how cosmic ray electron and positron energy losses via inverse Compton scattering and synchrotron radiation can be used to constrain the Galactic magnetic field and interstellar radiation field using recent observational data.

Contribution

It introduces an alternative method to constrain the Galactic magnetic field and interstellar radiation field based on cosmic ray and diffuse emission data.

Findings

Recent AMS-02, Fermi, and H.E.S.S. data can effectively constrain ISRF and GMF properties.

The impact of ISRF and GMF variations on cosmic ray spectra is quantifiable.

Observational data provides a new approach for understanding Galactic magnetic and radiation fields.

Abstract

High energy cosmic ray electrons and positrons, during propagation in the Galaxy, mainly lose energy through either the inverse Compton scattering (ICS) off of the interstellar radiation field (ISRF) or emitting synchrotron radiation in the Galactic magnetic field (GMF). Emitted photons by these two main energy loss mechanisms contribute to, respectively, diffuse Galactic gamma rays and radio waves. The variation of the distribution of the ISRF and the GMF has a sizable impact on the spectrum of cosmic ray electrons and positrons throughout the Galaxy. This impact is revealed both locally through measuring the local flux of cosmic ray electrons and positrons and globally by observing the spectra and morphology of diffuse gamma rays and radio waves. In this paper, we quantify this impact and conclude that recent data from AMS-02, \textit{Fermi} and H.E.S.S experiments are powerful enough to be alternatively applied for constraining properties of the ISRF and the GMF.