Clustering of ultra-high energy cosmic ray arrival directions on medium scales

• Published in: Astroparticle Physics
• Main Authors: Kachelriess, M., Semikoz, D.V.
• Other Authors: APC - THEORIE, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut für theoretische Physik, Universität Hamburg (UHH)-Universität Hamburg (UHH)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: 98.70.Sa; [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; Yakutsk
• Online Access: https://hal.in2p3.fr/in2p3-00025298; https://doi.org/10.1016/j.astropartphys.2006.04.006

11 pages, 5 figures The two-point autocorrelation function of ultra-high energy cosmic ray (UHECR) arrival directions has a broad maximum around 25 degrees, combining the data with energies above $4\times 10^{19}$ eV (in the HiRes energy scale) of the HiRes stereo, AGASA, Yakutsk and SUGAR experiments. This signal is not or only marginally present analyzing events of a single experiment, but becomes significant when data from several experiments are added. Both the energy dependence and the angular scale might be interpreted as first signature of the large-scale structure of UHECR sources and of intervening magnetic fields.