نتایج جستجو برای: galactic cosmic ray
تعداد نتایج: 349069 فیلتر نتایج به سال:
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...
In this article, the author proposes to consider a link between infant mortality rate (IMR) and galactic cosmic radiation (CR) density. The periodical increase in solar activity increases the effect of the magnetic field of the sun, and therefore weakens galactic cosmic rays hitting the Earth's surface. As a result, embryos in their early stages of development may be less exposed to high-energy...
Production of neutrons, neutrinos and gamma-rays by a very fast pulsar in the Galactic Center region
We consider the possibility that the excess of cosmic rays near ∼ 10 eV, reported by the AGASA and SUGAR groups from the direction of the Galactic Center, is caused by a young, very fast pulsar in the high density medium. The pulsar accelerates iron nuclei to energies ∼ 10 eV, as postulated by the Galactic models for the origin of the highest energy cosmic rays. The iron nuclei, after about 1 y...
Supernova remnants have long been regarded as sources of the Galactic cosmic rays up to petaelectronvolts, but convincing evidence is still lacking. In this work we explore the common origin of the subtle features of the cosmic ray spectra, such as the knee of cosmic ray spectra and the excesses of electron/positron fluxes recently observed by ATIC, H.E.S.S., Fermi-LAT and PAMELA. Numerical cal...
The contributions of different radiation mechanisms to the diffuse γ-ray emission of the galactic disk are studied in a broad energy region from 104 to 1014 eV. Our analysis shows that at energies between 1 and 100 MeV the radiation is dominated by the bremsstrahlung of relatively low energy, typically less than 1 GeV electrons, but with a non-negligible contribution from the inverse Compton (I...
UMN-TH-1924/00 TPI-MINN-00/48 CERN-TH/2000-288 astro-ph/0010121 October 2000 The recent observations of an approximately linear relationship between both Be and B and iron in metal poor stars has led to a reassessment of the origin of the light elements in the early Galaxy. In addition to standard secondary production of BeB, it is necessary to introduce a production mechanism which is independ...
We have observed a typical Galactic plane field at (l, b) = (2846,−020) with Suzaku for 100 ksec to carry out a precise spectral study of the Galactic Ridge X-ray Emission (GRXE). The field is known to be devoid of X-ray point sources brighter than ∼2×10ergs s cm (2–10 keV), and already deeply observed with Chandra. Thanks to the low and stable background and high spectral resolution of Suzaku,...
[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...
We explore the possibility that the diffuse gamma-ray background radiation (GBR) at high galactic latitudes could be dominated by inverse Compton scattering of cosmic ray (CR) electrons on the cosmic microwave background radiation and on starlight from our own galaxy. Assuming that the mechanisms accelerating galactic CR hadrons and electrons are the same, we derive simple and successful relati...
The Galactic cosmic-ray propagation code GALPROP is designed to make predictions of many kinds of data self-consistently, including direct cosmic-ray measurements, gamma rays and synchrotron radiation. In the decade since its conception it has undergone considerable development, which is continuing. A public version was made available a few years ago, supported by a website. We describe the new...
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