A new estimate of the Galactic interstellar radiation field between 0.1 microns and 1000 microns

TL;DR

This paper develops a detailed model of the Galactic interstellar radiation field from ultraviolet to infrared, incorporating stellar and dust distributions, to improve predictions of diffuse gamma-ray emission via inverse Compton scattering.

Contribution

It introduces a comprehensive model of the Galactic radiation field that includes absorption, scattering, and dust heating, enhancing accuracy over previous models.

Findings

Calculated radiation field spectra and distributions.

Provides a basis for more accurate gamma-ray emission predictions.

Self-consistent dust and stellar distribution modeling.

Abstract

Cosmic-ray electrons and positrons propagating in the Galaxy produce diffuse gamma-rays via the inverse Compton (IC) process. The low energy target photon populations with which the cosmic-rays interact during propagation are produced by stars, this stellar light being reprocessed by Galactic dust. Detailed modelling of the Galactic stellar distribution, dust distribution, and treatment of the absorption and scattering of light is therefore required to obtain accurate models for the low energy Galactic photon distribution and spectrum. Using a realistic Galactic stellar distribution model, and dust distribution, we calculate the diffuse radiation field from stars in the Galaxy (the `optical' radiation field), including absorption and scattering. Using a dust heating code, we self-consistently calculate the infra-red radiation field for the same dust model used for the optical calculation; both transient and equilibrium heating are included. We present the calculated radiation field spectra and distributions, and will use these to calculate the expected Galactic diffuse IC gamma-ray spectrum.