Signatures of ultra-high energy cosmic ray composition from propagation of nuclei in intergalactic photon fields

We present a calculation of nuclei propagation with energies above 1018 eV in the intergalactic photon field. The calculation is based on a Monte-Carlo approach for the nucleus–photon interaction as well as the intergalactic magnetic field. We then assume that the ultra-high energy cosmic rays (UHECR) are nuclei which are emitted from extra-galactic point sources. Four bumps are found in the energy spectrum of the UHECR which form clusters in the distribution of their arrival directions. Based on this calculation, the energy distribution of the clustered events is discussed.