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Poster communications

The ultra-high energy cosmic ray spectrum and Fermi shock acceleration.

M. Kachelriess D.V. Semikoz 1
APC (UMR_7164) - AstroParticule et Cosmologie, Institut für theoretische Physik
Abstract : The energy spectrum of ultra-high energy cosmic rays (UHECR) is usually calculated for sources with identical properties. Assuming that all sources can accelerate UHECR protons to the same extremely high maximal energy E_max > 10^{20} eV and have the steeply falling injection spectrum 1/E^{2.7}, one can reproduce the measured cosmic ray flux above E > 10^{18} eV. We show that relaxing the assumption of identical sources and using a power-law distribution of their maximal energy allows one to explain the observed UHECR spectrum with the injection 1/E^2 predicted by Fermi shock acceleration. We study possible ways to distinguish between these two cases with future experiments.
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Contributor : Simone Lantz <>
Submitted on : Tuesday, September 4, 2007 - 4:18:08 PM
Last modification on : Wednesday, October 21, 2020 - 4:32:14 PM


  • HAL Id : in2p3-00169707, version 1


M. Kachelriess, D.V. Semikoz. The ultra-high energy cosmic ray spectrum and Fermi shock acceleration.. Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia. 30th International Cosmic Ray Conference - ICRC'07, Jul 2007, Merida, Mexico. Universidad Nacional Autonoma De Mexico, 4, pp.487-490, 2008. ⟨in2p3-00169707⟩



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