Are AGN the Best Factories for High Energy Particles and Photons?

TL;DR

This paper reviews AGN properties, focusing on their potential as sources of ultra high energy particles and photons, highlighting that low luminosity and dormant AGN may be more effective than luminous ones.

Contribution

It proposes that low luminosity and dormant AGN, due to their jets, could be the primary sources of high energy particles and photons, challenging previous assumptions.

Findings

Low luminosity AGN can power strong jets capable of accelerating particles.

Dormant black holes in galaxy nuclei may be significant high energy particle sources.

AGN diversity affects their potential as high energy particle factories.

Abstract

The main properties of AGN are reviewed, focussing on the accretion process and on the question of whether AGN are the best factories of ultra high energy particles and photons. I recall the large differences between the accretion/ejection flows in strong and weak accretors, and I conclude that, since low luminosity AGN and even "dormant" massive black holes in nuclei of galaxies are powering strong confined magnetized jets able to accelerate high energy particles, and are present in a large proportion of galaxies, they might be better potential sources of high energy particles and photons than luminous AGN and powerful radio galaxies.