The energy spectrum observed by the AGASA experiment and the spatial distribution of the sources of ultra-high energy cosmic rays

Abstract

Seven and a half years of continuous monitoring of giant air showers triggered by ultra high-energy cosmic rays have been recently summarized by the AGASA collaboration. The resulting energy spectrum indicates clearly that the cosmic ray spectrum extends well beyond the Greisen-Zatsepin-Kuzmin (GZK) cut-off at $\sim 5\times 10^{19}$ eV. Furthermore, despite the small number statistics involved, some structure in the spectrum may be emerging. Using numerical simulations, it is demonstrated in the present work that these features are consistent with a spatial distribution of sources that follows the distribution of luminous matter in the local Universe. Therefore, from this point of view, there is no need for a second high-energy component of cosmic rays dominating the spectrum beyond the GZK cut-off.

14 pages, 4 figures, Astrophys. J. Letters (submitted)

References in corpus (9)

• Extension of the Cosmic-Ray Energy Spectrum Beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff
• Ultra-high energy cosmic rays without GZK cutoff
• Extremely high energy cosmic rays from relic particle decays
• Correlation between Compact Radio Quasars and Ultra-High Energy Cosmic Rays
• The Extremely High Energy Cosmic Rays
• Galactic Anisotropy as Signature of ``Top-Down'' Mechanisms of Ultra-High Energy Cosmic Rays
• The effect of highly structured cosmic magnetic fields on ultra-high energy cosmic ray propagation
• On the significance of the observed clustering of ultra-high energy cosmic rays
• Ultra High Energy Cosmic Rays

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• Origin and Propagation of Extremely High Energy Cosmic Rays
• The high energy cosmic ray spectrum from relic particle decay
• Ultrahigh Energy Cosmic Rays: The state of the art before the Auger Observatory
• The GZK Feature in our Neighborhood of the Universe
• UHECR propagation in the Galaxy: clustering versus isotropy
• The Anisotropy of the Ultra-High Energy Cosmic Rays
• Violation of Lorentz Invariance and neutral component of UHECR
• Ensemble Fluctuations of the Flux and Nuclear Composition of Ultra-High Energy Cosmic Ray Nuclei
• Unmasking the tail of the cosmic ray spectrum
• Ultra-high energy cosmic rays: from GeV to ZeV
• Uncorrelated far AGN flaring with their delayed UHECRs events