نتایج جستجو برای: cosmic ray
تعداد نتایج: 325747 فیلتر نتایج به سال:
Gamma ray bursts (GRBs) are astronomical phenomena detected at highest energies. The gamma photons carry energies on the order of mega-electronovolts and arrive to us from point-like sources that uniformly distributed sky. A typical burst has a form pulse lasts for about minute. As Earth atmosphere is not transparent very high energy radiation, by means telescopes onboard satellites placed orbi...
We briefly describe the energy loss processes of ultrahigh energy protons, heavier nuclei and gamma rays in interactions with the universal photon fields of the Universe. We then discuss the modification of the accelerated cosmic ray energy spectrum in propagation by the energy loss processes and the charged cosmic ray scattering in the extragalactic magnetic fields. The energy lost by the ultr...
Diffuse γ-ray radiation in galaxies is produced by cosmic ray interactions with the interstellar medium. With the completion of EGRET observations, the only extragalactic object from which there has been a positive detection of diffuse γ-ray emission is the Large Magellanic Cloud. We systematically estimate the expected diffuse γ-ray flux from Local Group galaxies, and determine their detectabi...
[1] A coronal mass ejection (CME) associated with an X17 solar flare reached Earth on October 29, 2003, causing an 11% decrease in the intensity of high-energy Galactic cosmic rays recorded by muon detectors. The CME also produced a strong enhancement of the cosmic ray directional anisotropy. Based upon a simple inclined cylinder model, we use the anisotropy data to derive for the first time th...
The existence of cosmic rays of energies exceeding 10 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 observations to models for the origin of high energy cosmic rays are reviewed, and the implications of recent new experimental results are discussed. Large area high...
The origin and structure of the Earth's crust is still a major question. Traditionally the nearby crust of the Earth has been explored in great detail with echo-sounding or gravimetric techniques. Current measurements are based largely on these techniques, which has intrinsic uncertainties. In the present talk, a novel method with cosmic-ray muons to create a direct snapshot of the density prof...
The atmosphere of the Earth is opaque to most wavelengths of light in the infrared, in the ultraviolet and in the X-rays. Due to this fact observation of celestial objects in X-rays (in the range of energies from 0.5 to 20 keV) must be carried out outside the atmosphere at altitudes greater than 100 kilometers, namely from space. The development of X-ray astronomy had therefore to await the dev...
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