نتایج جستجو برای: cosmic rays
تعداد نتایج: 69861 فیلتر نتایج به سال:
Stable lumps of quark matter may be present in cosmic rays at a flux level, which can be detected by high precision cosmic ray experiments sensitive to anomalous “nuclei” with high massto-charge ratio. The properties of these lumps, called strangelets, are described, and so is the production and propagation of strangelets in cosmic rays. Two experiments underway which are sensitive to a strange...
We consider the propagation of cosmic rays in turbulent magnetic fields. We use the models of magnetohydrodynamic turbulence that were tested in numerical simulations, in which the turbulence is injected on large scale and cascades to small scales. Our attention is focused on the models of the strong turbulence, but we also briefly discuss the effects that the weak turbulence and the slab Alfvé...
While supernova remnants have been identified as the most likely sources of the galactic cosmic rays, no conclusive observational evidence for this association exists. We show here that IceCube has the possibility of producing incontrovertible evidence by detecting neutrinos produced by the cosmic ray beam interacting with the hydrogen in the vicinity of the supernova shock expanding into the i...
A search was conducted for TeV -rays emitted from the direction of the ultra–high-energy cosmic ray detected by the Fly’s Eye experiment with energy E 3 1020 eV. No enhancement was found at a level of 10 10 cm 2 s 1 for E > 350 GeV. A steady source of ultra–high-energy cosmic ray protons or photons would be expected to produce a -ray flux above this level. An upper limit was also set for the fl...
The present situation with regard to experimental data on ultra high-energy cosmic rays is briefly reviewed. Whilst detailed knowledge of the shape of the energy spectrum is still lacking, it is clear that events above 10 20 eV do exist. Evidence for clustering of the directions of some of the highest energy events remains controversial. Clearly, more data are needed and these will come from th...
With the Akeno Giant Air Shower Array, 581 cosmic rays above 1019 eV, 47 above 4] 1019 eV, and seven above 1020 eV were observed until 1998 August. The arrival direction distribution of these extremely high energy cosmic rays has been studied. While no signiÐcant large-scale anisotropy is found on the celestial sphere, some interesting clusters of cosmic rays are observed. Above 4 ] 1019 eV, th...
I discuss recent advances being made in the physics and astrophysics of cosmic rays and cosmic γ-rays at the highest observed energies as well as the related physics and astrophysics of very high energy cosmic neutrinos. I also discuss the connections between these topics.
We consider the advantages of and the problems associated with hypotheses to explain the origin of ultrahigh energy cosmic rays (UHECR: E > 10 EeV) and the “trans-GZK” cosmic rays (TGZK: E > 100 EeV) both through (‘old physics” (acceleration in cosmic sources) and “new physics” (new particles, topological defects, fat neutrino cross sections, Lorentz invariance violation).
This work presents preliminary results for the time-dependent cosmic-ray propagation in the Galaxy by a fully 3-dimensional Monte Carlo simulation. The distribution of cosmic-rays (both protons and helium nuclei) in the Galaxy is studied on various spatial scales for both constant and variable cosmicray sources. The continuous diffuse gamma-ray emission produced by cosmic-rays during the propag...
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