Related papers: Clusters in Very High Energy Cosmic Rays
Extreme Energy Cosmic Rays, EECRs -- cosmic rays with energies beyond the GZK cutoff (i.e. greater than 100 EeV) are scarce. Only a few of such events have been detected by air shower experiments and the nature of the primary particles are…
The origin of Galactic cosmic rays (with energies up to 10^15 eV) remains unclear, though it is widely believed that they originate in the shock waves of expanding supernova remnants. Currently the best way to investigate their acceleration…
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…
The existence of cosmic rays of energies exceeding 10^20 eV is one of the mysteries of high energy astrophysics. The spectrum and the high energy to which it extends rule out almost all suggested source models. The challenges posed by…
It is proposed a new approach for estimating the composition of cosmic rays. It is found that the zenith angle distributions and muon components of EAS for energies E>10^19 eV and E>4.10^19 eV differ from each other. It is shown that the…
Extremely high energy (up to 10**(22) eV) cosmic neutrino beams initiate high energy particle cascades in the background of relic neutrinos from the Big Bang. We perform numerical calculations to show that such cascades could contribute…
The two-point autocorrelation function of ultra-high energy cosmic ray (UHECR) arrival directions has a broad maximum around 25 degrees, combining the data with energies above $4\times 10^{19}$ eV (in the HiRes energy scale) of the HiRes…
A correlation and probability analysis of the distribution of arrival directions for a sample of AGASA events reported to have energies above 4x10^{19} eV shows the small scale clustering to remain significant at the 99.5 - 99.9% CL and to…
We consider the recent results on UHECR (Ultra High Energy Cosmic Ray) composition and their distribution in the sky from ten EeV energy (the dipole anisotropy) up to the highest UHECR energies and their clustering maps: UHECR have been…
Ultrahigh-energy cosmic rays (UHECRs) arrive at Earth from the most energetic astrophysical accelerators in the universe. They collide with atoms in the upper atmosphere with energies about ten times higher than any man-made accelerator,…
Ultrahigh energy cosmic rays are the most energetic of any subatomic particles ever observed in nature. The quest for their mysterious origin is currently a major scientific challenge. Here we explore the possibility that these particles…
The latest observations of extensive air showers (EAS) induced by ultra-high-energy cosmic rays (UHECR) appear to indicate, prima facie, a transition to heavy primaries at the highest energies. However, this interpretation, which is based…
The runaway breakdown -- extensive atmospheric shower discharge (RB - EAS) excited in thunderstorm atmosphere by high energy cosmic ray particles ($\epsilon_p>10^{17} - 10^{19}$ eV) generate very powerful radio pulse. The RB - EAS theory is…
Stellar clusters are potential acceleration sites of very-high-energy (VHE, E > 100GeV) particles since they host supernova remnants (SNRs) and pulsar wind nebulae (PWNe). Additionally, in stellar clusters, particles can also be accelerated…
Recently the AGASA Collaboration presented data suggesting a significant clustering of ultra-high energy cosmic rays coming from the outer Galaxy region. In this paper we calculate expected cosmic ray arrival distributions for several…
Experimental results on ultra-high-energy cosmic rays are briefly reviewed and their interpretation is discussed. The results related to principal observables (arrival directions, energies and composition) of primary particles of extended…
The Earth is continuously showered by charged cosmic ray particles, naturally produced atomic nuclei moving with velocity close to the speed of light. Among these are ultra high energy cosmic ray particles with energy exceeding 5x10^19 eV,…
It is shown that the acceleration of particles by a powerful relativistic jet associated with the activity of a supermassive black hole in the Galactic center several million years ago may explain the observed cosmic ray spectrum at…
We study in detail the properties of clusters of ultra high energy cosmic ray events, looking in particular to their angular correlation function, to the relative frequency of clusters with different multiplicities (e.g. doublets vs.…
A simple model is exhibited in which the remnant density of charged vortons is used to provide candidates for explaining the observed ultra high energy cosmic rays (above $10^{20}$ eV). These vortons would be accelerated in active galaxies…