2007/02/18 by Graciela B. Gelmini, Graciela Gelmini, O. Kalashev +3 · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Neutrino Physics Research #astro-ph
paper · pdf · doi:10.1016/j.astropartphys.2007.08.006
published as Astropart.Phys.28:390-396,2007 · 13 pages, 9 figures
arxiv created 2007/02/18 · openalex publication_date 2007/09/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In a recently proposed model the cosmic rays spectrum at energies above 1018 eV can be fitted with a minimal number of unknown parameters assuming that the extragalactic cosmic rays are only protons with a power law source spectrum ~E-alpha and alpha~2.6. Within this minimal model, after fitting the observed HiRes spectrum with four parameters (proton injection spectrum power law index and maximum energy, minimum distance to sources and evolution parameter) we compute the flux of ultra-high energy photons due to photon-pion production, the GZK photons, for several radio background models and average extragalactic magnetic fields with amplitude between 10-11 G and 10-9 G. We find the photon fraction to be between 10-4 and 10-3 in cosmic rays at energies above 1019 eV. These small fluxes could only be detected in future experiments like Auger North plus South and EUSO.