Gamma-ray emission in radio galaxies, from MeV to TeV

TL;DR

Radio galaxies have become key objects in high-energy astrophysics due to recent gamma-ray observations, helping to understand jet structures, emission regions, and physical processes across MeV to TeV energies.

Contribution

This review compiles recent gamma-ray observations of radio galaxies from MeV to TeV, highlighting their significance and discussing future prospects with the Cherenkov Telescope Array.

Findings

Radio galaxies are confirmed as high-energy gamma-ray sources.

Jet orientation influences gamma-ray detectability.

Future CTA observations will enhance understanding of emission mechanisms.

Abstract

Thanks to the Fermi gamma-ray satellite and the current Imaging Atmospheric Cherenkov Telescopes, radio galaxies have arisen as a new class of high- and very-high energy emitters. The favourable orientation of their jets makes radio galaxies extremely relevant in addressing important issues such as: (i) revealing the jet structure complexity; (ii) localising the emitting region(s) of high- and very-high energy radiation; (iii) understanding the physical processes producing these photons. In this review the main results on the gamma-ray emission studies of radio galaxies from the MeV to TeV regimes will be presented, and the impact of future Cherenkov Telescope Array observations will be discussed.