Related papers: Final Results from the High Resolution Fly's Eye (…
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…
The paper describes methods used for the detection of cosmic rays with energies above 10^18 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3…
We report the results of a search for point-like deviations from isotropy in the arrival directions of ultra-high energy cosmic rays in the northern hemisphere. In the monocular data set collected by the High-Resolution Fly's Eye,…
The rarest cosmic rays above the GZK cut'off $(E_{CR} \tilde{>} 10^{19} \div 10^{20} eV)$ are probably born at cosmic distances ($\tilde{>}$ tens Mpc) by AGNs (QSRs, BLac, Blazars...). Their puzzling survival over $2.75 K^o$ BBR radio waves…
It is often claimed that there should be a 'GZK cut-off" in the flux of extragalactic cosmic rays, arising from interactions between the cosmic rays and the cosmic micro-wave background photons (e.g. 1 and 2). Some experiments (3 and 4)…
We calculate numerically the spectrum of ultra-high energy cosmic rays on Earth assuming that their sources are distributed in space like the observed galaxies. We use the CfA2 and the PSCz galaxy redshift surveys to model the local galaxy…
A prediction of standard Big Bang cosmology is that the observed UHECR (ultra-high-energy cosmic rays) spectrum will exhibit a cutoff at the GKZ limit, resulting from interaction with the photons that constitute the cosmic microwave…
Great advances have been made in the study of ultra-high energy cosmic rays (UHECR) in the past two decades. These include the discovery of the spectral cut-off near 5 x 10^19 eV and complex structure at lower energies, as well as…
The Telescope Array's Middle Drum fluorescence detector was constructed using refurbished telescopes from the High Resolution Fly's Eye (HiRes) experiment. As such, there is a direct comparison between these two experiments' fluorescence…
The GZK cutoff predicted at the Ultra High Energy Cosmic Ray (UHECR) spectrum as been observed by the HiRes and Auger experiments. The results put severe constraints on the effect of Lorentz Invariance Violation(LIV) which has been…
We study the spectrum and average mass composition of cosmic rays with primary energies between 10^{17} eV and 10^{18} eV using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array.…
We briefly discuss the implications of recent AUGER results for patterns of Lorentz symmetry violation (LSV), assuming that the existence of the Greisen-Zatsepin-Kuzmin cutoff is definitely confirmed. The mass composition of the…
Contrary to earlier expectations, several cosmic ray events with energies above $10^{20}$ eV have been reported by a number of ultra-high energy cosmic ray observatories. According to the AGASA experiment, the flux of such events is well…
In a recent letter [1] with the same title, Farrar and Piran offered an explanation for the near isotropy of the arrival directions [2] of ultrahigh energy cosmic rays (UHECRs) and the apparent absence [3] of the so called `GZK cutoff' in…
Based on a model for the emission of high energy cosmic rays from AGN (Active Galactic Nuclei) that has been proposed by the author, he reviews the status of the GZK cutoff and the correlation of high energy cosmic ray sources with AGN…
We investigate the injection spectrum of ultra-high-energy (>10^{15} eV) cosmic rays under the hypotheses that (1) these cosmic rays are protons and (2) the sources of these cosmic rays are extra-galactic and are homogeneously distributed…
The current measurements of the cosmic ray energy spectrum at ultra-high energies ($\text{E}>10^{19}$ eV) are characterized by large systematic errors and poor statistics. In addition, the experimental results of the two experiments with…
The High Resolution Fly's Eye HiRes-I detector has now been in operation in monocular mode for over six years. During that time span, HiRes-I has accumulated a larger exposure to Ultra-High Energy Cosmic Rays (UHECRs) above 10^19 eV than…
This paper begins with a pedagogical discussion of the propagation of cosmic rays and the showers produced when a cosmic ray primary hits the upper atmosphere. The paper focusses cosmic rays, with energy > 10^19 eV. Emphasis is placed on…
We demonstrate that the energy spectra of Ultra High Energy Cosmic rays (UHECR) as observed by AGASA, Fly's Eye, HiRes and Yakutsk detectors, have the imprints of UHE proton interaction with the CMB radiation in the form of the dip at…