Ultra-High Energy Gamma Rays in Geomagnetic Field and Atmosphere

Abstract

The nature and origin of ultra-high energy (UHE: reffering to > 10^19 eV) cosmic rays are great mysteries in modern astrophysics. The current theories for their explanation include the so-called "top-down" decay scenarios whose main signature is a large ratio of UHE gamma rays to protons. Important step in determining the primary composition at ultra-high energies is the study of air shower development. UHE gamma ray induced showers are affected by the Landau-Pomeranchuk-Migdal (LPM) effect and the geomagnetic cascading process. In this work extensive simulations have been carried out to study the characteristics of air showers from UHE gamma rays. At energies above several times 10^19 eV the shower is affected by geomagnetic cascading rather than by the LPM effect. The properties of the longitudinal development such as average depth of the shower maximum or its fluctuations depend strongly on both primary energy and incident direction. This feature may provide a possible evidence of the UHE gamma ray presence by fluorescence detectors.

arXiv comment27 pages, 12 figures, submitted to Phys.Rev.D

References in corpus (7)

• Origin and Propagation of Extremely High Energy Cosmic Rays
• Suppression of Bremsstrahlung and Pair Production due to Environmental Factors
• Signatures of Topological Defects
• Electromagnetic showers in a strong magnetic field
• The nature of the highest energy cosmic rays
• Characteristics of air showers created by extremely high energy gamma-rays
• The Future of Ultra High Energy Cosmic Rays

Cited by in corpus (12)

• Ultra-High-Energy Cosmic Rays
• The Jem-Euso Mission
• Search for ultra-high energy photons using air showers
• Search for Cross-Correlations of Ultra--High-Energy Cosmic Rays with BL Lacertae Objects
• Simulation of Ultra-High Energy Photon Propagation in the Geomagnetic Field
• High Energy Physics in the Atmosphere: Phenomenology of Cosmic Ray Air Showers
• The highest-energy cosmic rays
• $e^{+}{e}^{-}$ Pair Production from 10 GeV to 10 ZeV
• Primary Particle Type of the Most Energetic Fly's Eye Air Shower
• Characteristics of geomagnetic cascading of ultra-high energy photons at the southern and northern sites of the Pierre Auger Observatory
• Simulation of ultra-high energy photon propagation with PRESHOWER 2.0
• Discrepancies in the Monte Carlo simulations of propagation of ultra-high energy cosmic-ray photons in the geomagnetic field