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

Pedro Abreu, Marco Aglietta, Justin M. Albury, Ingomar Allekotte, Kevin Almeida Cheminant, Alejandro Almela, Jaime Alvarez-Muñiz, Rafael Alves Batista, Juan Ammerman Yebra, Gioacchino Alex Anastasi, Luis Anchordoqui, Belén Andrada (+363 others)
2022 The astrophysical journal 935(2)  
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 ≡ 10 18 eV). Despite the flux of these particles being extremely low, the area of ∼3000 km 2 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 ultrahigh-energy cosmic rays above 32 EeV. We
more » ... h this data set, the largest available at such energies from an integrated exposure of 122,000 km 2 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.
doi:10.18154/rwth-2022-09246 fatcat:atgetmqtinbqtjbnriasfg5kji