Origin of the ultrahigh-energy cosmic rays and their spectral break

Dado, S. and Dar, A. and De Rújula, A. (2012) Origin of the ultrahigh-energy cosmic rays and their spectral break. Il nuovo cimento C, 35 (1). pp. 89-95. ISSN 1826-9885

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The energy spectrum, composition and arrival directions of ultrahigh energy cosmic rays (UHECRs) with energy above the cosmic ray ankle, measured by the Pierre Auger Observatory, appear to be in conflict if their origin is assumed to be extragalactic. Their spectrum and composition, however, are those expected from Galactic UHECRs accelerated by highly relativistic jets such as those producing short hard gamma ray bursts (SHBs). If this alternative interpretation is correct, then the observed break in the energy spectrum of UHECRs around 50 EeV is the energy threshold for free escape of UHE iron nuclei from the Galaxy and not the Greisen-Zatsepin-Kuzmin (GZK) cutoff for protons, and the arrival directions of UHECR nuclei with energy above their UHE breaks must point back to their Galactic sources rather than to active galactic nuclei (AGN) within the GZK horizon.

Item Type: Article
Uncontrolled Keywords: Neutrino, muon, pion, and other elementary particles; cosmic rays ; γ-ray sources; γ-ray bursts
Subjects: 500 Scienze naturali e Matematica > 530 Fisica
Depositing User: Marina Spanti
Date Deposited: 14 Apr 2020 16:45
Last Modified: 14 Apr 2020 16:45
URI: http://eprints.bice.rm.cnr.it/id/eprint/17654

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