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تسجيل مستخدم جديدThe Anisotropy of Cosmic Ray Arrival Directions around 10$^{18}$eV
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Anisotropy in the arrival directions of cosmic rays with energies above 10$^{17}$eV is studied using data from the Akeno 20 km$^2$ array and the Akeno Giant Air Shower Array (AGASA), using a total of about 117,000 showers observed during 11 years. In the first harmonic analysis, we have found strong anisotropy of $sim$ 4% around 10$^{18}$eV, corresponding to a chance probability of 0.2%. With two dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region.
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Results are presented that were obtained by analysing the arrival directions of E0 > 8x10**18 eV primary cosmic rays recorded at the Yakutsk array over the period between 1974 and 2003 and at the SUGAR array (Australia). The greatest primary cosmic r
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Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using $3 times 10^4$ cosmic rays above $8 times 10^{18}
$ electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 square kilometers steradian year, we report an anisotropy in the arrival directions. The anisotropy, detected at more than the 5.2$sigma$ level of significance, can be described by a dipole with an amplitude of $6.5_{-0.9}^{+1.3}$% towards right ascension $alpha_{d} = 100 pm 10$ degrees and declination $delta_{d} = -24_{-13}^{+12}$ degrees. That direction indicates an extragalactic origin for these ultra-high energy particles.
Anisotropy in the arrival directions of cosmic rays around 10^{18}eV is studied using data from the Akeno 20 km^2 array and the Akeno Giant Air Shower Array (AGASA), using a total of about 216,000 showers observed over 15 years above 10^{17}eV. In th
e first harmonic analysis, we have found significant anisotropy of $sim$ 4 % around 10^{18}eV, corresponding to a chance probability of $sim 10^{-5}$ after taking the number of independent trials into account. With two dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region. This is a clear evidence for the existence of the galactic cosmic ray up to the energy of 10^{18}eV. Primary particle which contribute this anisotropy may be proton or neutron.
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