Arrival Directions of Cosmic Rays above 32 EeV from Phase One of the Pierre Auger Observatory

The Pierre Auger Collaboration

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A promising energy range to look for angular correlations between cosmic rays of extragalactic origin and their sources is at the highest energies, above a few tens of EeV (1 EeV 1018 eV). Despite the flux of these particles being extremely low, the area of ∼3000 km2 covered at the Pierre Auger Observatory, and the 17 yr data-taking period of the Phase 1 of its operations, have enabled us to measure the arrival directions of more than 2600 ultra-high-energy cosmic rays above 32 EeV. We publish this data set, the largest available at such energies from an integrated exposure of 122,000 km2 sr yr, and search it for anisotropies over the 3.4π steradians covered with the Observatory. Evidence for a deviation in excess of isotropy at intermediate angular scales, with ∼15° Gaussian spread or ∼25° top-hat radius, is obtained at the 4σ significance level for cosmic-ray energies above ∼40 EeV.

Original languageEnglish
Article number170
Number of pages24
Issue number2
Publication statusPublished - 1 Aug 2022

Bibliographical note

Funding Information:
The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargüe. We are very grateful to the following agencies and organizations for financial support:

Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.

Copyright 2022 Elsevier B.V., All rights reserved.


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