Centaurus A as a source of extragalactic cosmic rays with arrival energies well beyond the GZK cutoff

TL;DR

This paper suggests Centaurus A as a potential source of ultra-high energy cosmic rays exceeding the GZK cutoff, estimating particle energies up to 2.2×10^{21} eV and discussing future observational tests.

Contribution

It introduces a model linking Centaurus A to ultra-high energy cosmic rays and predicts detectable energies and directions for future observations.

Findings

Estimated cosmic ray energies up to 2.2×10^{21} eV.

Predicted arrival directions near galactic coordinates (310°, 20°).

Future observations by Pierre Auger Observatory could confirm the model.

Abstract

The ultra--high energy cosmic rays recently detected by several air shower experiments could have an extragalactic origin. In this case, the nearest active galaxy Centaurus A might be the source of the most energetic particles ever detected on Earth. We have used recent radio observations in order to estimate the arrival energy of the protons accelerated by strong shock fronts in the outer parts of this southern radio source. We expect detections corresponding to particles with energies up to $\sim 2.2 \times 10^{21}$ eV and an arrival direction of ($l \approx 310^{\circ}$, $b \approx 20^{\circ}$) in galactic coordinates. The future Southern Hemisphere Pierre Auger Observatory might provide a decisive test for extragalactic models of the origin of the ultra--high energy cosmic rays.