Flux and Mass Composition of Ultra-High Energy Cosmic Rays from Radio Galaxies

Nearby radio galaxies (RGs) with relativistic jets are considered promising candidates as sources of ultra-high-energy cosmic rays (UHECRs). By employing a novel double power-law model with an "extended" exponential cutoff to describe the energy spectrum of UHECRs escaping from RG jets, we evaluate the UHECR flux arriving at Earth from RGs both in the local universe and at cosmological distances. Our findings indicate that UHECRs reaching the northern hemisphere exhibit a higher flux and a lighter composition at the highest energies compared to those in the southern hemisphere. This discrepancy is likely due to Virgo A having a jet with a higher Lorentz factor than those of Centaurus A and Fornax A. These results may account for the observed differences in UHECR flux and mass composition between the Telescope Array and the Pierre Auger Observatory.