Related papers: Ultra-High Energy Cosmic Rays: Results and Prospec…
Cosmic rays around the so-called knee in the spectrum at around PeV primary energy are generally galactic in origin. Observations on the form of their energy spectrum and their mass composition are fundamental tools to understand the…
The sharp change in slope of the ultrahigh-energy cosmic ray spectrum around 10^{9.6} GeV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle which evolves to intermediate/heavy composition…
The sharp change in slope of the ultrahigh energy cosmic ray (UHECR) spectrum around 10^18.6 eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle and intermediate composition above, has…
The origin and nature of the ultrahigh energy cosmic rays (UHECRs) are still unknown. However, great progress has been achieved in past years due to the observations performed by the Pierre Auger Observatory and Telescope Array. Above…
In this paper we review the main features of the observed Cosmic Rays spectrum in the energy range $10^{17} {\rm eV}~\div~10^{20} {\rm eV}$. We present a theoretical model that explains the main observed features of the spectrum, namely the…
The most recent experimental results on the cosmic ray composition and energy spectrum above 1 TeV are reviewed and discussed. All data agree on the presence of the so-called ``knee'' at an energy E(knee) = 3-4 PeV; the knee is seen in all…
The differential energy spectrum of the cosmic radiation from solar modulation energies up to 5x10**19 eV is correctly predicted by a recent theory of the knee and ankle which uses only one normalization point. This remarkable quantitative…
A detailed investigation of radio galaxies has recently stressed these sources as the possible origin of the cosmic rays observed above $3\,\text{EeV}$. Here, the relevance of this model at energies below $3\,\text{EeV}$ is investigated.…
The high energy spectrum of cosmic rays presents three distinct traits, the second knee, the ankle, and the GZK cutoff and as such, a thorough understanding of cosmic rays encompasses the study of these three features. It is in the second…
Neutrinos from far away sources annihilating at the Z resonance on relic neutrinos may give origin to the ultrahigh-energy cosmic rays. Here we present predictions of this mechanism with relic neutrinos lighter than 1 eV, which do not…
The field of ultra-high energy cosmic rays made a lot of progresses last years with large area experiments such as the Pierre Auger Observatory, HiRes and the Telescope Array. A suppression of the cosmic ray flux at energies above…
Cosmic rays around the knee are generally believed to be of galactic origin. Observations on their energy spectrum and chemical composition are important for understanding the acceleration and propagation of these cosmic rays. In addition,…
The significant attenuation of the cosmic-ray flux above $\sim 5 10^{19}$ eV suggests that the observed high-energy spectrum is shaped by the so-called GZK effect. This interaction of ultra-high-energy cosmic rays (UHECRs) with the ambient…
The impressive power-law decay of the energy spectrum of cosmic rays over more than thirty orders of magnitude in intensity and for energies ranging over eleven decades between $\simeq 10^9 $eV and $\simeq 10^{20} $eV is actually dotted…
The signatures of UHE proton propagation through CMB are pair-production dip and GZK cutoff. The visible manifestations of these spectral features are ankle, beginning of GZK cutoff in the differential spectrum and E_{1/2} in integral…
We review the basic ideas on the origin of cosmic rays with energy in excess of $\sim 10^{19}$ eV, in the light of the most recent observational findings. The limited statistics of events detected by the two largest experiments currently…
We have argued [J. Szabelski et al. (2002)] that the well-known `ankle' in the cosmic ray energy spectrum, at logE (eV) ~ 18.7-19.0, marks the transition from mainly Galactic sources at lower energies to mainly extragalactic above.…
We have developed a model that explains cosmic rays with energies E between \~0.3 PeV and the energy of the second knee at E_2 ~ 3*10^{17} eV as originating from a recent Galactic gamma-ray burst (GRB) that occurred ~1 Myr ago within 1 kpc…
The present situation with regard to experimental data on ultra high-energy cosmic rays is briefly reviewed. Whilst detailed knowledge of the shape of the energy spectrum is still lacking, it is clear that events above 10^20 eV do exist.…
The search for a theory of the origin of cosmic rays that may be considered as a standard, agreeable model is still ongoing. On one hand, much circumstantial evidence exists of the fact that supernovae in our Galaxy play a crucial role in…