Ultra-High-Energy Cosmic Rays from the Radio Lobes of AGNs

Abstract

In the past year, the HiRes and Auger collaborations have reported the discovery of a high-energy cutoff in the ultra-high energy cosmic-ray (UHECR) spectrum, and an apparent clustering of the highest energy events towards nearby active galactic nuclei (AGNs). Consensus is building that such $\sim 10^{19}$--$10^{20}$ eV particles are accelerated within the radio-bright lobes of these sources, but it is not yet clear how this actually happens. In this paper, we report (to our knowledge) the first treatment of stochastic particle acceleration in such environments from first principles, showing that energies $\sim 10^{20}$ eV are reached in $\sim 10^6$ years for protons. However, our findings reopen the question regarding whether the high-energy cutoff is due solely to propagation effects, or whether it does in fact represent the maximum energy permitted by the acceleration process itself.

8 pages, 7 figures, acccepted for publication in MNRAS

References in corpus (4)

• On Active Galactic Nuclei as Sources of Ultra-High Energy Cosmic Rays
• A Possible Link Between the Galactic Center HESS Source and Sgr A*
• GZK Photons in the Minimal Ultra High Energy Cosmic Rays Model
• Diffuse TeV Emission at the Galactic Centre

Cited by in corpus (6)

• High-energy Particle Acceleration and Production of Ultra-high-energy Cosmic Rays in the Giant Lobes of Centaurus A
• Ultra High Energy Cosmic Rays from Black Hole Jets of Radio Galaxies
• Decoding the giant extragalactic radio sources
• The Centaurus A Ultrahigh-Energy Cosmic Ray Excess and the Local Extragalactic Magnetic Field
• Non-thermal transient sources from rotating black holes
• On Estimating the Flux of the Brightest Cosmic Ray Source above 57x10^18 eV