Ultrahigh energy nuclei propagation in a structured, magnetized universe

We compare the propagation of iron and proton nuclei above 10(19) eV in a structured Universe with source and magnetic field distributions obtained from a large-scale structure simulation and source densities similar to 10(-5) Mpc(-3). All relevant cosmic ray interactions are taken into account, including photo-disintegration and propagation of secondary products. Iron injection predicts spectral shapes different from proton injection which disagree with existing data below similar or equal to 30 EeV. Injection of light nuclei or protons must therefore contribute at these energies. However, at higher energies, existing data are consistent with injection of pure iron with spectral indices between similar to 2 and similar to 2.4. This allows a significant recovery of the spectrum above similar or equal to 100 EeV, especially in the case of large deflections. Significant autocorrelation and anisotropy, and considerable cosmic variance are also predicted in this energy range. The mean atomic mass fluctuates considerably between different scenarios. At energies below 60 EeV, if the observed A greater than or similar to 35, magnetic fields must have a negligible effect on propagation. At the highest energies the observed flux will be dominated by only a few sources whose location may be determined by next generation experiments to within 10-20 degrees even if extra-galactic magnetic fields are important.