Search for Large-scale Anisotropy on Arrival Directions of Ultra-high-energy Cosmic Rays Observed with the Telescope Array Experiment
Rasha Abbasi, Mitsuru Abe, T. Abu‐Zayyad, M. Allen, R. Azuma, E. Barcikowski, John Belz, D. R. Bergman, S. A. Blake, R. Cady, B. G. Cheon, J. Chiba, M. Chikawa, Armando di Matteo, Toshihiro Fujii, Kozo Fujisue, K. Fujita, Ryota Fujiwara, M. Fukushima, G. Furlich, W. Hanlon, Motoki Hayashi, N. Hayashida, K. Hibino, R. Higuchi, K. Honda, D. Ikeda, Taichi Inadomi, Naoko Inoue, Takaaki Ishii, R. Ishimori, Hirotaka Ito, D. Ivanov, Hirokazu Iwakura, Hyeonju Jeong, S. Jeong, C. C. H. Jui, K. Kadota, F. Kakimoto, O. Kalashev, K. Kasahara, Saori Kasami, H. Kawai, S. Kawakami, S. Kawana, K. Kawata, E. Kido, Jihyun Kim, J. H. Kim, Jihyun Kim, M. H. Kim, S. W. Kim, S. Kishigami, V. Kuzmin, M. Kuznetsov, Y.-J. Kwon, K. H. Lee, Б. Лубсандоржиев, Jon Paul Lundquist, K. Machida, Hiroyuki Matsumiya, T. Matsuyama, J. N. Matthews, R. Mayta, M. Minamino, K. Mukai, I. Myers, Shigehiro Nagataki, Kei Nakai, R. Nakamura, T. Nakamura, Yuya Nakamura, Yuya Nakamura, T. Nonaka, Hiroyuki Oda, S. Ogio, M. Ohnishi, H. Ohoka, Yuya Oku, T. Okuda, Y. Omura, M. Ono, R. Onogi, A. Oshima, S. Ozawa, Il Han Park, М. С. Пширков, Jackson Remington, D. C. Rodriguez, Г. И. Рубцов, Dongsu Ryu, H. Sagawa, Ryosuke Sahara, Yasunori Saito, Н. Сакаки, T. Sako, N. Sakurai, Kengo Sano, T. Seki, K. Sekino
Abstract
Abstract Motivated by the detection of a significant dipole structure in the arrival directions of ultra-high-energy cosmic rays above 8 EeV reported by the Pierre Auger Observatory (Auger), we search for a large-scale anisotropy using data collected with the surface detector array of the Telescope Array Experiment (TA). With 11 yr of TA data, a dipole structure in a projection of the R.A. is fitted with an amplitude of 3.3% ± 1.9% and a phase of 131° ± 33°. The corresponding 99% confidence-level upper limit on the amplitude is 7.3%. At the current level of statistics, the fitted result is compatible with both an isotropic distribution and the dipole structure reported by Auger.