The Extremely High Energy Cosmic Rays

Experimental results from Haverah Park, Yakutsk, AGASA and Fly’s Eye are reviewed. All these experiments work in the energy range above 10 17 eV. The ’dip ’ structure around 10 18.5 eV in the energy spectrum is well established by all the experiments, though the exact position differs slightly. Fly’...

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Bibliographic Details
Main Authors: Shigeru Yoshida A, Hongyue Dai B
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 1998
Subjects:
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.257.2288
http://arxiv.org/pdf/astro-ph/9802294v1.pdf
Description
Summary:Experimental results from Haverah Park, Yakutsk, AGASA and Fly’s Eye are reviewed. All these experiments work in the energy range above 10 17 eV. The ’dip ’ structure around 10 18.5 eV in the energy spectrum is well established by all the experiments, though the exact position differs slightly. Fly’s Eye and Yakutsk results on the chemical composition indicate that the cosmic rays are getting lighter over the energy range from 10 17 eV to 10 19 eV, but the exact fraction is hadronic interaction model dependent, as indicated by the AGASA analysis. The arrival directions of cosmic rays are largely isotropic, but interesting features may be starting to emerge. Most of the experimental results can best be explained with the scenario that an extragalactic component gradually takes over a galactic population as energy increases and cosmic rays at the highest energies are dominated by particles coming from extragalactic space. However, identification of the extragalactic sources has not yet been successful because of limited statistics and the resolution of the data. subject headings: cosmic rays: general 1