Ultra-High Energy Heavy Nuclei Propagation in Extragalactic Magnetic   Fields
  We extend existing work on the propagation of ultra-high energy cosmic rays in extragalactic magnetic fields to a possible component of heavy nuclei, taking into account photodisintegration, pion production, and creation of e+e- pairs. We focus on the influence of the magnetic field on the spectrum and chemical composition of observed ultra-high energy cosmic rays. We apply our simulations to the scenarios proposed by Anchordoqui et al, in which Iron nuclei are accelerated in nearby starburst galaxies, and show that it is in marginal agreement with the data. We also show that it is highly unlikely to detect He nuclei from M87 at the highest energies observed $\sim3 10^{20} $eV as required for the scenario of Ahn et al. in which the highest energy cosmic rays originate from M87 and are deflected in a Parker spiral Galactic magnetic field. 
Gianfranco Bertone, Claudia Isola, Martin Lemoine, Guenter Sigl