Iron Nuclei in Ultra-High Energy Cosmic Rays Near the Earth

The propagation of cosmic iron nuclei with energies above 10^19 eV from their sources to the Galaxy is discussed by assuming that cosmic rays at ultra-high energies are of extragalactic origin. In extragalactic space, cosmic nuclei interact with background emissions and inevitably fragment. An analysis is performed of the fraction of iron nuclei reaching the Earth and how its energy depends on the distance from cosmic ray sources. It is found that energies of iron nuclei can be used to determine restriction on the distances from their sources