Non-thermal emission in lobes of radio galaxies: III. 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236

TL;DR

This paper models the non-thermal electron populations in the lobes of six radio galaxies to predict their gamma-ray emission via inverse Compton scattering, enhancing understanding of high-energy processes in these structures.

Contribution

It provides detailed modeling of non-thermal electron properties and gamma-ray emission estimates for six radio galaxy lobes, based on radio and X-ray data.

Findings

Properties of intra-lobe non-thermal electrons are fully determined.

Gamma-ray emission levels from inverse Compton scattering are estimated.

Models constrain the leptonic origin of gamma-ray emission in radio galaxy lobes.

Abstract

Recent analyses of the broad spectral energy distributions (SED) of extensive lobes of local radio-galaxies have confirmed the leptonic origin of their Fermi/LAT gamma-ray emission, significantly constraining the level of hadronic contribution. SED of distant (D > 125 Mpc) radio-galaxy lobes are currently limited to the radio and X-ray bands, hence give no information on the presence of non-thermal (NT) protons but are adequate to describe the properties of NT electrons. Modeling lobe radio and X-ray emission in 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236, we fully determine the properties of intra-lobe NT electrons and estimate the level of the related gamma-ray emission from Compton scattering of the electrons off the superposed Cosmic Microwave Background, Extragalactic Background Light, and source-specific radiation fields.