2007/03/31 by G. Sigl, Guenter Sigl · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Neutrino Physics Research #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.75.103001
published as Phys.Rev.D75:103001,2007 · 9 revtex pages, 9 figures, published version, minor changes
openalex publication_date 2007/05/07 · arxiv created 2007/05/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Analytical calculations of extragalactic cosmic ray spectra above \ensuremath∼1017 eV are often performed assuming continuous source distributions, giving rise to spectra that depend little on the propagation mode, be it rectilinear or diffusive. We perform trajectory simulations for proton primaries in the probably more realistic case of discrete sources with a density of \ensuremath∼10^\ensuremath-5 Mpc^\ensuremath-3. We find two considerable nonuniversal effects that depend on source distributions and magnetic fields: First, the primary extragalactic cosmic ray flux can become strongly suppressed below a few 1018 eV due to partial confinement in magnetic fields surrounding sources. Second, the secondary photon to primary cosmic ray flux ratio between \ensuremath≃3\ifmmode×\else\texttimes\fi1018 eV and \ensuremath≃1020 eV decreases with decreasing source density and increasing magnetization. As a consequence, in acceleration scenarios for the origin of highest energy cosmic rays the fraction of secondary photons may be difficult to detect even for experiments such as Pierre Auger. The cosmogenic neutrino flux does not significantly depend on source density and magnetization.