Related papers: Ultra-High Energy Cosmic Rays: Results and Prospec…
Recent results from the Pierre Auger Observatory are presented, focusing on a measurement of the cosmic-ray energy spectrum above 10^18 eV, cosmic-ray composition, and the anisotropy in the cosmic ray arrival directions. The flux of cosmic…
Recent work suggests that the cosmic ray spectrum may be dominated by Galactic sources up to ~10^{17.5} eV, and by an extra-Galactic component beyond, provided this latter cuts off below the transition energy. Here it is shown that this…
We investigate the dependence of composition, spectrum and angular distributions of ultra-high energy cosmic rays above 10^19 eV from individual sources on their magnetization. We find that, especially for sources within a few megaparsecs…
We consider the scenario in which the knee in the cosmic ray spectrum is due to a change in the escape mechanism of cosmic rays from the Galaxy from one dominated by transverse diffusion to one dominated by drifts. We show that this…
Understanding the acceleration of Ultra High Energy Cosmic Rays is one of the great challenges of contemporary astrophysics. In this short review, we summarize the general observational constraints on their composition, spectrum and…
The origin of the knee in the energy spectrum of cosmic rays is an outstanding problem in astroparticle physics. Numerous mechanisms have been proposed to explain the structure in the all-particle spectrum. In the article basic ideas of…
The analysis of cosmic rays fluxes as a function of energy reveals a {\it knee} slightly below $10^{16}$ eV and an {\it ankle} close to $10^{19}$ eV. Their physical origins remain up to now quite enigmatic; in particular, no elementary…
The energy spectrum, composition and arrival directions of ultrahigh energy cosmic rays (UHECRs) with energy above the cosmic ray ankle, measured by the Pierre Auger Observatory, are inconsistent if their origin is assumed to be…
In this work we present the interpretation of the energy spectrum and mass composition data as measured by the Pierre Auger Collaboration above $6 \times 10^{17}$ eV. We use an astrophysical model with two extragalactic source populations…
This is a summary of a series of lectures on the current experimental and theoretical status of our understanding of origin and nature of cosmic radiation. Specific focus is put on ultra-high energy cosmic radiation above ~10^17 eV,…
The results from the first three years observation in Telescope Array are reviewed. The energy spectrum, mass composition, and anisotropy in arrival directions of ultra-high energy cosmic rays are discussed. The energy spectrum of cosmic…
Analytical calculations of extra-galactic cosmic ray spectra above ~10^17 eV are often performed assuming continuous source distributions, giving rise to spectra that depend little on the propagation mode, be it rectilinear or diffusive. We…
Ultra-high-energy cosmic rays (UHECRs) are atomic nuclei from space with vastly higher energies than any other particles ever observed. Their origin and chemical composition remain a mystery. As we show here, the large- and…
We study the anisotropies on large angular scales which can be present in the flux of cosmic rays reaching the Earth from a population of extragalactic sources, focusing on the energy range between the second knee and the ankle. In this…
While there is some level of consensus on a Galactic origin of cosmic rays up to the knee ($E_{k}\sim 3\times 10^{15}$ eV) and on an extragalactic origin of cosmic rays with energy above $\sim 10^{19}$ eV, the debate on the genesis of…
Experimental results from Haverah Park, Yakutsk, AGASA and Fly's Eye are reviewed. All these experiments work in the energy range above 0.1 EeV. The 'dip' structure around 3 EeV in the energy spectrum is well established by all the…
Recent results from the KASCADE experiment on measurements of cosmic rays in the energy range of the knee are presented. Emphasis is placed on energy spectra of individual mass groups as obtained from an two-dimensional unfolding applied to…
We show that the second knee in the cosmic ray spectrum (i.e. the steepening occurring at $E\simeq 4\times 10^{17}$ eV) could be related to drift effects affecting the heaviest nuclear component, the iron group nuclei, in a scenario in…
The origin of cosmic rays with energies higher than 10$^{20}$ eV remains a mystery. Accelerating particles up to these energies is a challenge even for the most energetic astrophysical objects known. While the isotropy in arrival directions…
In this paper we briefly discuss the problem of the origin of Ultra High Energy Cosmic Rays in the framework of Top-Down models. We show that, for high energy of decays and in a wide range of spectra of injected protons, their extragalactic…