The Centaurus A Ultrahigh-Energy Cosmic Ray Excess and the Local Extragalactic Magnetic Field

Abstract

The ultrahigh-energy cosmic-ray anisotropies discovered by the Pierre Auger Observatory give the potential to finally address both the particles' origins and properties of the nearby extragalactic magnetic field (EGMF). We examine the implications of the excess of ~ 10^20 eV events around the nearby radio galaxy Centaurus A. We find that, if Cen A is the source of these cosmic rays, the angular distribution of events constrains the EGMF strength within several Mpc of the Milky Way to > 20 nG for an assumed primary proton composition. Our conclusions suggest that either the observed excess is a statistical anomaly or the local EGMF is stronger then conventionally thought. We discuss the implications of this field, including UHECR scattering from more distant sources, time delays from transient sources, and the possibility of using magnetic lensing signatures to attain tighter constraints.

8 pages, 8 figures; Matches published version in APJ

References in corpus (9)

• 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
• Anisotropy vs chemical composition at ultra-high energies
• Propagation of UHE Protons through Magnetized Cosmic Web
• Comment on "Correlation of the Highest-Energy Cosmic Rays with Nearby Extragalactic Objects"
• Distortion of Ultra-high-energy sky by Galactic Magnetic Field
• Cross-Correlation between UHECR Arrival Distribution and Large-Scale Structure
• Ultra-High-Energy Cosmic Rays from the Radio Lobes of AGNs
• Correlation of the HIghest Energy Cosmic Rays with the Supergalactic Plane

Cited by in corpus (2)

• The Gamma-Ray Window to Intergalactic Magnetism
• Images of the Ultra-High Energy Cosmic Rays from Point Sources