2003/04/11 by Pasquale Blasi, Blasi, Pasquale
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0304206
Invited Review Talk at the XXI Texas Symposium, December 2002, Florence, Italy
arxiv created 2003/04/11 · arxiv updated 2009/12/01
We review the basic ideas on the origin of cosmic rays with energy in excess of ∼ 1019 eV, in the light of the most recent observational findings. The limited statistics of events detected by the two largest experiments currently operating does not allow as yet to claim the detection of the GZK feature in the cosmic ray spectrum or the lack of it. Although extragalactic point sources seem to be preferred on the basis of the small scale anisotropies detected by AGASA, the possibility that UHECRs with energy in excess of 1020 eV may be the result of the decay of supermassive particles is not ruled out by present data. It seems clear that if we want to have a clear idea of the origin of UHECRs, we have to auspicate the realization of larger, better experiments, such as the ongoing Auger project and the space-borne EUSO experiment.