Related papers: Extragalactic cosmic-ray source composition and th…
We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear…
Extragalactic cosmic ray protons with an injection spectrum of the type $E^{-2.7}$ show a spectrum on earth with a dip due to the Bethe-Heitler pair production against the photons of the cosmic microwave background. The dip is produced in…
We study the phenomenology of cosmic-rays (CRs) at the galactic/extragalactic transition, focusing on two opposite models for the composition of the extragalactic (EG) component. Model A assumes a mixed source composition, with nuclear…
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…
It has recently been suggested that ultra-high energy cosmic rays could have an extragalactic origin down to the "second knee" at ~4x10^{17}eV. In this case the "ankle" or "dip" at ~5x10^{18}eV would be due to pair production of…
In this paper, we study the propagation of cosmic-ray nuclei and protons. We emphasize the influence of the source composition on the expected spectrum and composition on Earth as well as on the phenomenology of the transition from Galactic…
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…
Understanding the transition from Galactic to extragalactic cosmic rays (CRs) is essential to make sense of the Local cosmic ray spectrum. Several models have been proposed to account for this transition in the 0.1 - 10 $\times 10^{18}$ eV…
We discuss the differences induced by the assumed composition of extragalactic sources on the predicted UHECR spectrum and the energy evolution of $<X_{\max}>$, i.e. the mean value of the atmospheric depth at the cosmic-ray air shower…
We use a kinetic-equation approach to describe the propagation of ultra high energy cosmic ray protons and nuclei and calculate the expected spectra and mass composition at the Earth for different assumptions on the source injection spectra…
The sharp change in slope of the ultra-high 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 which evolves to intermediate composition…
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…
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.…
Recent advances in measuring and interpreting cosmic rays from the spectral ankle to the highest energies are briefly reviewed. A knee of heavy primaries and an ankle of light primaries have been observed at about 10^{17} eV. The light…
In this paper, a probable interpretation of a remarkable fine structure of all particle spectra between the knee and the ankle, as well as a high content of heavy nuclei around 10^17 eV measured recently in Tunka-133 and KASCADE Grande…
We have carried out a detailed study to understand the observed energy spectrum and composition of cosmic rays with energies up to ~10^18 eV. Our study shows that a single Galactic component with subsequent energy cut-offs in the individual…
We examine the question of the origin of the Galactic cosmic-rays (GCRs) in the light of the data available at the highest energy end of the spectrum. We argue that the data of the Pierre Auger Observatory and of the KASCADE-Grande…
The energy at which cosmic rays from extra-galactic sources begin to dominate over those from galactic sources is an important open question in astroparticle physics. A natural candidate is the energy at the 'ankle' in the approximately…
Observations of cosmic rays have been improved at all energies, both in terms of higher statistics and reduced systematics. As a result, the all particle cosmic ray energy spectrum starts to exhibit more structures than could be seen…
In this article we examine the hypothesis that the highest energy cosmic rays are complex nuclei from extragalactic sources. Under reasonable physical assumptions, we show that the nearby metally rich starburst galaxies (M82 and NGC 253)…