Disappointing model for ultrahigh-energy cosmic rays

Abstract

Data of Pierre Auger Observatory show a proton-dominated chemical composition of ultrahigh-energy cosmic rays spectrum at (1 - 3) EeV and a steadily heavier composition with energy increasing. In order to explain this feature we assume that (1 - 3) EeV protons are extragalactic and derive their maximum acceleration energy, E_p^{max} \simeq 4 EeV, compatible with both the spectrum and the composition. We also assume the rigidity-dependent acceleration mechanism of heavier nuclei, E_A^{max} = Z x E_p^{max}. The proposed model has rather disappointing consequences: i) no pion photo-production on CMB photons in extragalactic space and hence ii) no high-energy cosmogenic neutrino fluxes; iii) no GZK-cutoff in the spectrum; iv) no correlation with nearby sources due to nuclei deflection in the galactic magnetic fields up to highest energies.

4 pages, 7 figures, the talk presented by A. Gazizov at NPA5 Conference, April 3-8, 2011, Eilat, Israel

References in corpus (2)

• A dip in the UHECR spectrum and the transition from galactic to extragalactic cosmic rays
• Analytic calculations of the spectra of ultra high energy cosmic ray nuclei. II. The general case of background radiation

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• Extragalactic propagation of ultrahigh energy cosmic-rays
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• Extragalactic cosmic rays and their signatures
• Active Galactic Nuclei Jets and Multiple Oblique Shock Acceleration: Starved Spectra
• Acceleration and propagation of ultrahigh energy cosmic rays
• Multilevel Bayesian framework for modeling the production, propagation and detection of ultra-high energy cosmic rays