Update on tests of the Cen A neutron-emission model of highest energy cosmic rays

TL;DR

This paper updates the neutron-emission model for the highest energy cosmic rays from Cen A, showing it fits current data and can be tested further with future observations.

Contribution

It introduces an updated model of neutron emission from Cen A explaining high-energy cosmic rays, consistent with recent Pierre Auger data.

Findings

Neutron emission from Cen A can account for observed cosmic ray anisotropy.

Required cosmic ray luminosity is much lower than Cen A's bolometric luminosity.

Future data will be able to test the proposed model.

Abstract

We propose that neutron emission from Cen A dominates the cosmic ray sky at the high end of the spectrum. Neutrons that are able to decay generate proton diffusion fronts, whereas those that survive decay produce a spike in the direction of the source. We use recent data reported by the Pierre Auger Collaboration to normalize the injection spectrum and estimate the required luminosity in cosmic rays. We find that such a luminosity, L_{CR} ~ 5 x 10^{40} erg/s, is considerably smaller than the bolometric luminosity of Cen A, L_{bol} ~ 10^{43} erg/s. We compute the incoming current flux density as viewed by an observer on Earth and show that the anisotropy amplitude is in agreement with data at the 1\sigma level. Regardless of the underlying source model, our results indicate that after a decade of data taking the Pierre Auger Observatory will be able to test our proposal.