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Title: INDICATIONS OF INTERMEDIATE-SCALE ANISOTROPY OF COSMIC RAYS WITH ENERGY GREATER THAN 57 EeV IN THE NORTHERN SKY MEASURED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT

We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 yr period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20° radius circles. The hotspot has a Li-Ma statistical significance of 5.1σ, and is centered at R.A. = 146.°7, decl. = 43.°2. The position of the hotspot is about 19° off of the supergalactic plane. The probability of a cluster of events of 5.1σ significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7 × 10{sup –4} (3.4σ)
Authors:
; ; ; ; ; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ; ;  [9] ;  [10] more »; « less
  1. High Energy Astrophysics Institute and Department of Physics and Astronomy, University of Utah, Salt Lake City, UT (United States)
  2. The Graduate School of Science and Engineering, Saitama University, Saitama, Saitama (Japan)
  3. Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo (Japan)
  4. Department of Physics and Institute for the Early Universe, Ewha Womans University, Seodaaemun-gu, Seoul (Korea, Republic of)
  5. Department of Physics and The Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul (Korea, Republic of)
  6. Department of Physics, Tokyo University of Science, Noda, Chiba (Japan)
  7. Department of Physics, Kinki University, Higashi Osaka, Osaka (Japan)
  8. Department of Physics, Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of)
  9. Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba (Japan)
  10. Graduate School of Science, Osaka City University, Osaka, Osaka (Japan)
Publication Date:
OSTI Identifier:
22365492
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 790; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ANISOTROPY; COSMIC RADIATION; COSMIC RAY DETECTION; EEV RANGE; PROBABILITY; TELESCOPES; UNIVERSE