Inhomogeneous extragalactic magnetic fields and the second knee in the cosmic ray spectrum
- Institut d'Astrophysique de Paris UMR7095 - CNRS, Universite Pierre and Marie Curie, 98 bis boulevard Arago F-75014 Paris (France)
Various experiments indicate the existence of a second knee around energy E=3x10{sup 17} eV in the cosmic ray spectrum. This feature could be the signature of the end of the galactic component and of the emergence of the extragalactic one, provided that the latter cuts off at low energies. Recent analytical calculations have shown that this cutoff could be a consequence of the existence of extragalactic magnetic fields (Refs. [M. Lemoine, Phys. Rev. D 71, 083007 (2005).][R. Aloisio and V. Berezinsky, Astrophys. J. 625, 249 (2005).]): low energy protons diffuse on extragalactic magnetic fields and cannot reach the observer within a given time. We study the influence of inhomogeneous magnetic fields on the magnetic horizon, using a new semianalytical propagation code. Our results indicate that, at a fixed value of the volume averaged magnetic field <B>, the amplitude of the low energy cutoff is mainly controlled by the strength of magnetic fields in the voids of the large-scale structure distribution.
- OSTI ID:
- 21035784
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 77, Issue 2; Other Information: DOI: 10.1103/PhysRevD.77.023005; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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