# Compton X-ray and Gamma-ray Emission from Extended Radio Galaxies

## TL;DR

This paper predicts that extended radio galaxy lobes emit X-ray and gamma-ray radiation via inverse Compton scattering, and such emissions could be detectable and imageable with the GLAST LAT instrument, providing new insights into these structures.

## Contribution

It introduces a model estimating gamma-ray emission from radio galaxy lobes based on radio measurements, highlighting potential detectability with GLAST LAT.

## Key findings

- Lobe spectra extend into soft gamma-rays for magnetic fields >~0.3-1 micro-G
- Predicted gamma-ray emissions are detectable with GLAST LAT
- Large angular extents allow imaging of radio lobes in gamma-rays

## Abstract

The extended lobes of radio galaxies are examined as sources of X-ray and gamma-ray emission via inverse Compton scattering of 3K background photons. The Compton spectra of two exemplary examples, Fornax A and Centaurus A, are estimated using available radio measurements in the ~10's MHz - 10's GHz range. For average lobe magnetic fields of >~0.3-1 micro-G, the lobe spectra are predicted to extend into the soft gamma-rays making them likely detectable with the GLAST LAT. If detected, their large angular extents (~1 deg and 8 deg) will make it possible to ``image'' the radio lobes in gamma-rays. Similarly, this process operates in more distant radio galaxies and the possibility that such systems will be detected as unresolved gamma-ray sources with GLAST is briefly considered.