Particles of primary cosmic radiation generating extensive air showers of energy above 10<Superscript>20</Superscript> eV in the atmosphere

In order to construct the energy spectrum on the basis of data from the Yakutsk array, a method similar to that employed at the AGASA array is applied in addition to the standard approach based on experimental procedures. Moreover, a new, original, method underlying the calculation of the spectrum in the region of energies above 10²⁰ eV is used to estimate energies. In order to compare data obtained at different arrays, it is proposed to harness the universal spectrum based on HiRes data. Within the QGSJET2 model, it is shown that a shower of energy 2 × 10²⁰ eV was observed at the Yakutsk array. In the same energy region (above 2 × 10²⁰ eV), the AGASA array recorded four showers, while the Fly’s Eye array and Pierre Auger Observatory (PAO) recorded one shower each. These data do not confirm the conclusion that the flux of primary-cosmic-ray particles decreases because of the Greisen-Zatsepin-Kuzmin effect.     

Ultra-High Energy Cosmic Ray Study Results by Radio Emission Technique at Yakutsk Array

Physics of Atomic Nuclei - The Yakutsk array is designed to study cosmic rays at energy 1015–1020 eV. The array detects charged particles, muons, Cherenkov light and radio emission....     

Composition of Cosmic Rays with Energy More than 0.1 EeV by Long-Term Optical Observations of Cherenkov Emission at Yakutsk EAS Array

Physics of Atomic Nuclei - The paper presents results on longitudinal development of air showers with ultra-high energies and mass composition of cosmic rays 〈ln A〉. The data is...     

Second Knee on the Spectrum of Cosmic Ray at Energies ∼1017 eV by Long-Term Observations of Small Cherenkov EAS Array

Physics of Atomic Nuclei - The paper presents the cosmic ray spectrum by the Small Cherenkov Yakutsk array data for 20 years of continuous observation. It has been shown by measurements that in the...     

Cosmic ray spectrum obtained from the energy scattered by the particles of extensive air showers in the atmosphere and the galactic model

The differential energy spectrum of cosmic rays that is obtained on the basis of the measurements of Cherenkov radiation from extensive air showers in an energy range of 10¹⁵–10²⁰ eV is compared with the model of the propagation of primary particles in the interstellar medium with fractal properties. It is found that the shape of the experimental spectrum is in good agreement with the shape of the calculated spectrum of “all particles” at 10¹⁵–10¹⁸ eV. The average mass composition of cosmic rays that is calculated on the basis of five components does not contradict the average mass composition obtained from the experimental data for several parameters in this energy range.     

Testing calculation results of Cherenkov radiation flux from extensive air showers using CORSIKA

This paper presents computational results of the spatiotemporal characteristics of Cherenkov light from particles of extensive air showers (EASs) induced by ultra-high-energy cosmic rays (UHECR). These results were obtained by simulating EAS events with the CORSIKA software package. Events were induced by UHECR particles, i.e., protons and iron nuclei with energies of 10¹⁵ and 10¹⁶ eV. The computational results were compared with experimental data obtained at the Yakutsk EAS array; possible causes of the discrepancy between them are discussed.     

Main results of the study of ultrahigh-energy cosmic rays in the Yakutsk Extensive Air Shower Array

This paper describes the current state of the Yakutsk Extensive Air Shower Array (EASA) and the prospects for its modernization. The main results of the study of the energy spectrum, mass composition, and anisotropy of the ultra-high energy cosmic rays (UHECRs) that were obtained recently by the array are given.     

A search for extragalactic sources of cosmic rays in the ultra-high energy domain

The arrival directions of ultra-high energy cosmic rays detected with the Yakutsk extensive air shower array are analyzed in comparison with the available data from other giant arrays. A correlation with the coordinates of active galaxy nuclei as hypothesized sources of ultra-high energy cosmic rays is sought for.     

Estimation of the energy of the electron-photon component of cosmic rays on the basis of data for Cherenkov light from ultrahigh-energy extensive air showers

The energy fraction E _em/E ₀ dissipated to the electron-photon component of extensive air showers (EASs) for E ₀=10¹⁵?10¹⁹ eV is estimated using data on Cherenkov radiation and charged particles from the Yakutsk EAS array. The results are compared with models with different dissipations to the electron-photon component and with calculations for various primary nuclei. In the energy range 10¹⁵?10¹⁶ eV and 10¹⁸?10¹⁹ eV, the ratio E _em/E ₀ is equal to 77 ± 2 and 88 ± 2, respectively, in agreement with the mixed and proton contents of primary cosmic rays in the former and latter energy ranges, respectively.     

Estimate of the Integral Photon Flux in the Region of Extremely High Energies in Complex Yakutsk EAS Array Data

A complex analysis of Yakutsk EAS array data has been performed in order to search for primary photons generating extensive air showers with energies above 10¹⁸ eV. Analyzing calculations and experimental data, selection criteria have been formulated and used to make a sample of showers close in their characteristics to showers initiated by primary photons. An upper limit of the integral photon flux in cosmic rays of extremely high energies has been estimated from these data.