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Anisotropies of ultra-high energy cosmic ray nuclei diffusing from extragalactic sources

High Energy Astrophysical Phenomena 2015-09-30 v1

Abstract

We obtain the dipolar anisotropies in the arrival directions of ultra-high energy cosmic ray nuclei diffusing from nearby extragalactic sources. We consider mixed-composition scenarios in which different cosmic ray nuclei are accelerated up to the same maximum rigidity, so that E<ZEmaxpE<ZE_\text{max}^p, with ZZ the atomic number and EmaxpE_\text{max}^p the maximum proton energy. We adopt Emaxp6E_\text{max}^p\simeq 6 EeV so as to account for an increasingly heavier composition above the ankle. We obtain the anisotropies through Monte Carlo simulations that implement the cosmic ray diffusion in extragalactic turbulent fields as well as the effects of photo-disintegrations and other energy losses. Dipolar anisotropies at the level of 5 to 10\% at energies 10\sim 10~EeV are predicted for plausible values of the source density and magnetic fields.

Keywords

Cite

@article{arxiv.1507.06585,
  title  = {Anisotropies of ultra-high energy cosmic ray nuclei diffusing from extragalactic sources},
  author = {Diego Harari and Silvia Mollerach and Esteban Roulet},
  journal= {arXiv preprint arXiv:1507.06585},
  year   = {2015}
}