Related papers: Extragalactic cosmic-ray source composition and th…
Over the last decade, observations have shown that the mean mass of ultra-high-energy cosmic rays (UHECRs) increases progressively toward the highest energies. However, the precise composition is still unknown, and several theoretical…
Suppose that even the highest energy cosmic rays (CRs) observed on Earth are protons accelerated in local Milky Way Galaxy sources, with few if any from more distant sources. In this paper we treat the problem that supernovae remnants…
Resonant photopion production with the cosmic microwave background predicts a suppression of extragalactic protons above the famous Greisen-Zatsepin-Kuzmin cutoff at about E_{GZK} ~ 5 x 10^10 GeV. Current cosmic ray data measured by the…
We demonstrate that the UHECRs produced in the nuclear cascade in the jet of Low-Luminosity Gamma-Ray Bursts (LL-GRBs) can describe the UHECR spectrum and composition and, at the same time, the diffuse neutrino flux at the highest energies.…
We explore inferences on ultrahigh energy cosmic ray (UHECR) source environments -- constrained by the spectrum and composition of UHECRs and non-observation of extremely high energy neutrinos -- and their implications for the observed high…
We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the…
We have published the energy spectrum of ultra-high energy cosmic rays (UHECRs) for E > 10^18.2 eV from our first 5-year observation with the surface detectors of Telescope Array. We found two breaking points in the power-law spectrum, a…
The origin and composition of ultra-high-energy cosmic rays (UHECRs) remain a mystery. The proton dip model describes their spectral shape in the energy range above $10^9$ GeV by pair production and photohadronic interactions with the…
We study the proton flux expected from sources of ultra high energy cosmic rays (UHECR) in the presence of regular extragalactic magnetic fields. It is assumed that a local source of ultra-high energy protons and the magnetic field are all…
The clustering of ultrahigh energy (>10^{20} eV) cosmic rays (UHECR) suggests that they might be emitted by compact sources. Statistical analysis (Dubovsky et al., 2000) estimated the source density. We extend their analysis to give also…
Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above ~ 6x10^{19} electron volts and the positions of active galactic…
We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic…
We study the extragalactic protons with universal spectrum, which is independent of mode of propagation, when distance between sources is less than the propagation lengths, such as energy attenuation length or diffusion length (for…
A model is introduced, in which the irregularity spectrum of the Galactic magnetic field beyond the dissipation length scale is first a Kolmogorov spectrum $k^{-5/3}$ at small scales $\lambda \, = \, 2 \pi/k$ with $k$ the wave-number, then…
Recent progress suggests we are moving towards a quantitative understanding of the whole cosmic ray spectrum, and that many bumps due to different components and processes hide beneath a relatively smooth total flux between knee and ankle.…
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…
We review the physics of the highest energy cosmic rays. The discovery of their sources, still unknown, will reveal the most energetic astrophysical objects in the universe and could unveil new physics beyond the standard model of particle…
Some new developments obtained in the last few years concerning the propagation of high energy cosmic rays are discussed. In particular, it is shown how the inclusion of drift effects in the transport diffusion equations leads naturally to…
We present the results of new calculations of the energy spectra of cosmic ray electrons, positrons and also positron fraction under assumption that both electrons and positrons are generated by the same Galactic sources, which accelerate…
Cosmic rays begin to reveal their secrets at energies above 5 EeV. Beyond this characteristic energy, known as the spectral "ankle", the arrival-direction data from the Pierre Auger Observatory show anisotropy on large angular scales of…