The High Energy View of FR0 Radio Galaxies

TL;DR

FR0 radio galaxies are a newly identified, abundant class of low-power sources with limited jets, potentially significant contributors to high-energy cosmic phenomena, and are promising targets for upcoming gamma-ray and neutrino observations.

Contribution

This paper reviews the properties of FR0 radio galaxies and predicts their high-energy emissions, highlighting their importance for future observational campaigns.

Findings

FR0s are five times more numerous than FRIs in the local universe.

They are potential sources of gamma rays and neutrinos.

FR0s could significantly contribute to the extragalactic gamma-ray background.

Abstract

A new class of low-power compact radio sources with limited jet structures, named FR0, is emerging from recent radio-optical surveys. This abundant population of radio galaxies, five times more numerous than FRIs in the local Universe (z$<$0.05), represent a potentially interesting target at high and very-high energies (greater than 100 GeV), as demonstrated by a single case of Fermi detection. Furthermore, these radio galaxies have been recently claimed to contribute non-negligibly to the extra-galactic $\gamma$-ray background and to be possible cosmic neutrino emitters. Here, we review the radio through X-ray properties of FR0s to predict their high-energy emission (from MeV to TeV), in light of the near-future facilities operating in this band.