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Title: Observation of small-scale anisotropy in the arrival direction distribution of TeV cosmic rays with HAWC

The High-Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays and charged cosmic rays at TeV energies. The detector is still under construction, but data acquisition with the partially deployed detector started in 2013. An analysis of the cosmic-ray arrival direction distribution based on 4.9 × 10{sup 10} events recorded between 2013 June and 2014 February shows anisotropy at the 10{sup –4} level on angular scales of about 10°. The HAWC cosmic-ray sky map exhibits three regions of significantly enhanced cosmic-ray flux; two of these regions were first reported by the Milagro experiment. A third region coincides with an excess recently reported by the ARGO-YBJ experiment. An angular power spectrum analysis of the sky shows that all terms up to ℓ = 15 contribute significantly to the excesses.
Authors:
 [1] ; ;  [2] ; ;  [3] ; ; ;  [4] ;  [5] ;  [6] ; ; ;  [7] ;  [8] ;  [9] ; ;  [10] ;  [11] ; ;  [12] more »; ; « less
  1. Department of Physics and Astronomy, Michigan State University, East Lansing, MI (United States)
  2. Instituto de Física, Universidad Nacional Autónoma de México, Mexico D.F. (Mexico)
  3. CEFyMAP, Universidad Autónoma de Chiapas, Tuxtla Gutiérrez, Chiapas (Mexico)
  4. Universidad Michoacana de San Nicolás de Hidalgo, Morelia (Mexico)
  5. Department of Physics, Michigan Technological University, Houghton, MI (United States)
  6. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT (United States)
  7. Department of Physics, University of Maryland, College Park, MD (United States)
  8. Universidad Politécnica de Pachuca, Pachuca, Hidalgo (Mexico)
  9. Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States)
  10. Instituto Nacional de Astrofísica, Óptica y Electrónica, Tonantzintla, Puebla (Mexico)
  11. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico D.F. (Mexico)
  12. Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Puebla (Mexico)
Publication Date:
OSTI Identifier:
22370151
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 796; 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; ANISOTROPY; COSMIC RADIATION; COSMIC RAY FLUX; DATA ACQUISITION; DISTRIBUTION; GAMMA RADIATION; MAPS; SPECTRA; TEV RANGE