The anisotropy of cosmic ray arrival directions around 10(18) eV

Authors
Hayashida, N Nagano, M Nishikawa, D Ohoka, H Sakaki, N Sasaki, M Takeda, M Teshima, M Torii, R Yamamoto, T Yoshida, S Honda, K Kawasumi, N Tsushima, I Inoue, N Kusano, E Shinozaki, K Souma, N Kadota, K Kakimoto, F Kamata, K Kawaguchi, S Kawasaki, Y Kitamura, H Matsubara, Y Matsubara, Y Murakami, K Uchihori, Y Yoshii, H
Citation
N. Hayashida et al., The anisotropy of cosmic ray arrival directions around 10(18) eV, ASTROPART P, 10(4), 1999, pp. 303-311
Citations number
13
Categorie Soggetti
Space Sciences
Journal title
ASTROPARTICLE PHYSICS
ISSN journal
09276505 → ACNP
Volume
10
Issue
4
Year of publication
1999
Pages
303 - 311
Database
ISI
SICI code
0927-6505(199905)10:4<303:TAOCRA>2.0.ZU;2-F
Abstract
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 Gi ant Air Shower Array (AGASA), using a total of about 114 000 showers observ ed over 11 years. In the first harmonic analysis, we have found a strong an isotropy of similar to 4% around 10(18) eV, corresponding to a chance proba bility of similar to 0.2% after taking the number of independent trials int o account. With two-dimensional analysis in right ascension and declination , this anisotropy is interpreted as an excess of showers near the direction s of the Galactic Center and the Cygnus region. (C) 1999 Elsevier Science B .V.