# High-Energy Cosmic Rays from Radio Galaxies

## TL;DR

This paper explores the role of radio galaxies as sources of cosmic rays below 3 EeV, showing they can explain flux levels but not the observed composition variations, suggesting the need for additional sources or models.

## Contribution

It provides a detailed analysis of radio galaxies' contribution to cosmic rays below 3 EeV, highlighting limitations in explaining composition changes and variance.

## Key findings

- Radio galaxies can explain CR flux between the second knee and ankle with strong source evolution.
- The model fails to reproduce the increasing heaviness and variance of chemical composition below 1 EeV.
- Discrepancies in composition variance suggest Centaurus A and Cygnus A contributions should be more similar.

## Abstract

A detailed investigation of radio galaxies has recently stressed these sources as the possible origin of the cosmic rays observed above $3\,\text{EeV}$. Here, the relevance of this model at energies below $3\,\text{EeV}$ is investigated. So, 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 $\lesssim 1\,\text{EeV}$ 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.