HAL : in2p3-00025291, version 1
 arXiv : astro-ph/0506128
 GZK Photons as Ultra High Energy Cosmic RaysGelmini G., Kalashev O., Semikoz D.V.Journal of Experimental and Theoretical Physics (JETP) / Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki 106 (2008) 1061-1082 - http://hal.in2p3.fr/in2p3-00025291
 Physique/Astrophysique/Cosmologie et astrophysique extra-galactique Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique
GZK Photons as Ultra High Energy Cosmic Rays
G. Gelmini, O. Kalashev, D.V. Semikoz1
 1 : APC - UMR 7164 - AstroParticule et Cosmologie http://www.apc.univ-paris7.fr/ CNRS : UMR7164 – IN2P3 – Observatoire de Paris – Université Paris VII - Paris Diderot – CEA : DSM/IRFU APC - UMR 7164, Université Paris Diderot, 10 rue Alice Domon et Léonie Duquet, case postale 7020, F-75205 Paris Cedex 13 France
APC - THEORIE
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.

Articles dans des revues avec comité de lecture
2008
 Journal of Experimental and Theoretical Physics (JETP) / Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki Publisher MAIK Nauka/Interperiodica (МАИК Наука/Интерпериодика) ISSN 1063-7761 (eISSN : 1090-6509)
106
1061-1082