Evidence for a Supergalactic Structure of Magnetic Deflection Multiplets of Ultra-high-energy Cosmic Rays

/ Authors

Telescope Array Collaboration R.U. Abbasi, M. Abe, T. Abu-Zayyad, M. Allen, R. Azuma, E. Barcikowski, J. Belz, D. Bergman, S. Blake, R. Cady

and 258 more authors

B. Cheon, J. Chiba, M. Chikawa, A. Matteo, T. Fujii, K. Fujisue, K. Fujita, R. Fujiwara, M. Fukushima, G. Furlich, W. Hanlon, M. Hayashi, Y. Hayashi, N. Hayashida, K. Hibino, R. Higuchi, K. Honda, D. Ikeda, T. Inadomi, N. Inoue, T. Ishii, R. Ishimori, H. Ito, D. Ivanov, H. Iwakura, H. Jeong, S. Jeong, C. Jui, K. Kadota, F. Kakimoto, O. Kalashev, K. Kasahara, S. Kasami, H. Kawai, S. Kawakami, S. Kawana, K. Kawata, E. Kido, H. Kim, J. H. Kim, M. H. Kim, S. W. Kim, S. Kishigami, V. Kuzmin, M. Kuznetsov, Y. Kwon, K. H. Lee, B. Lubsandorzhiev, J. Lundquist, K. Machida, K. Martens, H. Matsumiya, T. Matsuyama, J. Matthews, R. Mayta, M. Minamino, K. Mukai, I. Myers, S. Nagataki, K. Nakai, R. Nakamura, T. Nakamura, Y. Nakamura, T. Nonaka, H. Oda, S. Ogio, M. Ohnishi, H. Ohoka, Y. Oku, T. Okuda, Y. Omura, M. Ono, R. Onogi, A. Oshima, S. Ozawa, I. H. Park, M. Pshirkov, J. Remington, D. Rodríguez, G. Rubtsov, D. Ryu, H. Sagawa, R. Sahara, Y. Saito, N. Sakaki, T. Sako, N. Sakurai, K. Sano, L. Scott, T. Seki, K. Sekino, P. Shah, F. Shibata, T. Shibata, H. Shimodaira, B. Shin, H. Shin, J. Smith, P. Sokolsky, N. Sone, B. Stokes, S. Stratton, T. Stroman, T. Suzawa, Y. Takagi, Y. Takahashi, M. Takamura, R. Takeishi, A. Taketa, M. Takita, Y. Tameda, H. Tanaka, K. Tanaka, M. Tanaka, Y. Tanoue, S. Thomas, G. Thomson, P. Tinyakov, I. Tkachev, H. Tokuno, T. Tomida, S. Troitsky, Y. Tsunesada, Y. Uchihori, S. Udo, T. Uehama, F. Urban, T. Wong, K. Yada, M. Yamamoto, H. Yamaoka, K. Yamazaki, J. Yang, K. Yashiro, M. Yosei, H. Yoshii, Y. Zhezher, Z. Institute, Department of Applied Physics, Astronomy, U. Utah, Salt lake City, Utah., Usa, T. Z. F. O. Science, Engineering, S. University, Saitama, Japan., Graduate School of Science, Tokyo Institute of Technology, Meguro, Tokyo, T. Z. F. O. Science, Hanyang University, Seongdong-gu, Seoul., Korea, Tokyo University of Science, Noda, Chiba, K. University, Higashi Osaka, Osaka, Service de Physique Th'eorique, Universit́e Libre de Bruxelles, Brussels, Belgium, T. Research, K. University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto, Inst. for Nucl. Research, U. Tokyo, Kashiwa, O. University, K. I. F. T. Physics, M. Universe, Todai Institutes for Advanced Study, Information Science, Technology, Shinshu University, Nagano, Faculty of Electrical Engineering, Kanagawa University, Yokohama, Kanagawa, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Kofu, Yamanashi, E. Institute, Bunkyo-ku, A. G. S. O. Science, Technology Institute of Engineering, Astrophysical Big Bang Laboratory, Riken, Wako, S. University, Jang-an-gu, Suwon, T. University, Setagaya-ku, Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia., Faculty of Electrical Engineering, Science, Shibaura Institute of Technology, Minato-ku, Department of Materials Science, O. University, Neyagawa-shi, C. University, Yonsei University, Seodaemun-gu, F. Science, K. University, Kochi, Nambu Yoichiro Institute of Theoretical, E. Physics, D. Sciences, R. University, Kusatsu, Shiga, Advanced Research Institute for Science, Waseda University, Shinjuku-ku, Sternberg Astronomical Institute, M. University, School of Physical Sciences, Ulsan National Institute of Science, UNIST-gil, Ulsan, Rutgers University - The State University of New Jersey, Piscataway, N. Jersey., G. S. O. Sciences, H. University, Hiroshima, Institute of Particle, Nuclear Studies, Kek, Tsukuba, Ibaraki, National Institute of Advanced Industrial Science, Ceico, I. O. Physics, C. A. O. Sciences, Prague, Czech Republic, Institute for Fundamental Physics of the Universe, Ewha Womans University, Seodaaemun-gu, E. University, Matsuyama, Ehime

/ Abstract

Evidence for a large-scale supergalactic cosmic-ray multiplet (arrival directions correlated with energy) structure is reported for ultra-high-energy cosmic-ray (UHECR) energies above 1019 eV using 7 years of data from the Telescope Array (TA) surface detector and updated to 10 years. Previous energy–position correlation studies have made assumptions regarding magnetic field shapes and strength, and UHECR composition. Here the assumption tested is that, because the supergalactic plane is a fit to the average matter density of the local large-scale structure, UHECR sources and intervening extragalactic magnetic fields are correlated with this plane. This supergalactic deflection hypothesis is tested by the entire field-of-view (FOV) behavior of the strength of intermediate-scale energy–angle correlations. These multiplets are measured in spherical cap section bins (wedges) of the FOV to account for coherent and random magnetic fields. The structure found is consistent with supergalactic deflection, the previously published energy spectrum anisotropy results of the TA (the Hotspot and Coldspot), and toy-model simulations of a supergalactic magnetic sheet. The seven year data posttrial significance of this supergalactic structure of multiplets appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be 4.2σ. The 10 years of data posttrial significance is 4.1σ. Furthermore, the starburst galaxy M82 is shown to be a possible source of the TA Hotspot, and an estimate of the supergalactic magnetic field using UHECR measurements is presented.

Journal: The Astrophysical Journal

DOI: 10.3847/1538-4357/aba26c