158 articles – 1993 Notices  [english version]
 HAL : in2p3-00025291, version 1
 arXiv : astro-ph/0506128
 Journal of Experimental and Theoretical Physics (JETP) / Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki 106 (2008) 1061-1082
 GZK Photons as Ultra High Energy Cosmic Rays
 (2008)
 We calculate the flux of "GZK-photons", namely the flux of Ultra High Energy Cosmic Rays (UHECR) consisting of photons produced by extragalactic nucleons through the resonant photoproduction of pions, the so called GZK effect. We show that, for primary nucleons, the GZK photon fraction of the total UHECR flux is between $10^{-4}$ and $10^{-2}$ above $10^{19}$ eV and up to 0.6 above $10^{20}$ eV. The GZK photon flux depends on the assumed UHECR spectrum, slope of the nucleon flux at the source, distribution of sources and intervening backgrounds. Detection of this photon flux would open the way for UHECR gamma-ray astronomy. Detection of a larger photon flux would imply the emission of photons at the source or new physics. We compare the photon fractions expected for GZK photons and the minimal predicted by Top-Down models. We find that the photon fraction at $10^{20}$ eV is a crucial test for Top-Down models.
 équipe(s) de recherche : APC - THEORIE
 Thème(s) : Physique/Astrophysique/Cosmologie et astrophysique extra-galactiquePlanète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique
 Lien vers le texte intégral : http://fr.arXiv.org/abs/astro-ph/0506128
 in2p3-00025291, version 1 http://hal.in2p3.fr/in2p3-00025291 oai:hal.in2p3.fr:in2p3-00025291 Contributeur : Simone Lantz <> Soumis le : Mercredi 4 Janvier 2006, 15:38:53 Dernière modification le : Lundi 2 Juillet 2012, 18:18:11