High-Energy Cosmic Rays from Radio Galaxies

A detailed investigation of radio galaxies has recently stressed these sources as the possible origin of the cosmic rays observed above 3 EeV. Here, the relevance of this model at energies below 3 EeV is investigated. It is shown that the average contribution of radio galaxies can accurately explain the observed CR flux between the second knee and the ankle in the case of a strong source evolution. However, the model cannot provide the increasing heaviness and variance at energies ≲ 1 EeV of the observed chemical composition. In addition, it is exposed that the resulting variance of the chemical composition at Earth shows also at higher energies a clear disagreement with the observations, indicating that the compositional contributions by Centaurus A and Cygnus A need to be less different.