140 research outputs found
GZK photons as UHECR above 10 eV
"GZK photons" are produced by extragalactic nucleons through the resonant
photoproduction of pions. We present the expected range of the GZK photon
fraction of UHECR, assuming a particular UHECR spectrum and primary nucleons,
and compare it with the minimal photon fraction predicted by Top-Down models.Comment: Talk given at TAUP2005, Sept. 10-14 2005, Zaragoza (Spain); 3 pages,
2 figure
Photons as Ultra High Energy Cosmic Rays ?
We study spectra of the Ultra High Energy Cosmic Rays assuming primaries are
protons and photons, and that their sources are extragalactic. We assume power
low for the injection spectra and take into account the influence of cosmic
microwave, infrared, optical and radio backgrounds as well as extragalactic
magnetic fields on propagation of primaries. Our additional free parameters are
the maximum energy of injected particles and the distance to the nearest
source. We find a parameter range where the Greisen-Zatsepin-Kuzmin cut-off is
avoided.Comment: 4 pages, 4 figure
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