TY - JOUR
T1 - Large-scale and multipolar anisotropies of cosmic rays detected at the Pierre Auger Observatory with energies above 4 EeV
AU - Pierre Auger Collaboration
AU - de Almeida, R. M.
AU - Abreu, P.
AU - Aglietta, M.
AU - Albury, J. M.
AU - Allekotte, I.
AU - Almela, A.
AU - Alvarez-Muñiz, J.
AU - Alves Batista, R.
AU - Anastasi, G. A.
AU - Anchordoqui, L.
AU - Andrada, B.
AU - Andringa, S.
AU - Aramo, C.
AU - Araújo Ferreira, P. R.
AU - Arteaga Velázquez, J. C.
AU - Asorey, H.
AU - Assis, P.
AU - Avila, G.
AU - Badescu, A. M.
AU - Bakalova, A.
AU - Balaceanu, A.
AU - Barbato, F.
AU - Barreira Luz, R. J.
AU - Becker, K. H.
AU - Bellido, J. A.
AU - Berat, C.
AU - Bertaina, M. E.
AU - Bertou, X.
AU - Biermann, P. L.
AU - Binet, V.
AU - Bismark, K.
AU - Bister, T.
AU - Biteau, J.
AU - Blazek, J.
AU - Bleve, C.
AU - Boháčová, M.
AU - Boncioli, D.
AU - Bonifazi, C.
AU - Bonneau Arbeletche, L.
AU - Borodai, N.
AU - Botti, A. M.
AU - Brack, J.
AU - Bretz, T.
AU - Brichetto Orchera, P. G.
AU - Briechle, F. L.
AU - Buchholz, P.
AU - Bueno, A.
AU - Buitink, S.
AU - Buscemi, M.
AU - Mostafá, M.
N1 - Publisher Copyright:
© Copyright owned by the author(s) under the terms of the Creative Commons.
PY - 2022/3/18
Y1 - 2022/3/18
N2 - More than half a century after the discovery of ultra-high energy cosmic rays (UHECRs), their origin is still an open question. The study of anisotropies in the arrival directions of such particles is an essential ingredient to solve this puzzle. We update our previous analysis of large-scale anisotropies observed by the Pierre Auger Observatory using the latest data collected before the AugerPrime upgrade. We select events with zenith angles up to 80 degrees, implying a sky coverage of 85%, and energies above 4 EeV, for which the surface detector of the Observatory is fully efficient. Dipolar and quadrupolar amplitudes are evaluated through a combined Fourier analysis of the event count rate in right ascension and azimuth. The analysis is performed in three energy bins with boundaries at 4, 8, 16 and 32 EeV and two additional cumulative bins with energies above 8 and 32 EeV. The most significant signal is a dipolar modulation in right ascension for energies above 8 EeV, as previously reported, with statistical significance of 6.6σ. Additionally, we report the measurements of the angular power spectrum for the same energy bins with the same dataset.
AB - More than half a century after the discovery of ultra-high energy cosmic rays (UHECRs), their origin is still an open question. The study of anisotropies in the arrival directions of such particles is an essential ingredient to solve this puzzle. We update our previous analysis of large-scale anisotropies observed by the Pierre Auger Observatory using the latest data collected before the AugerPrime upgrade. We select events with zenith angles up to 80 degrees, implying a sky coverage of 85%, and energies above 4 EeV, for which the surface detector of the Observatory is fully efficient. Dipolar and quadrupolar amplitudes are evaluated through a combined Fourier analysis of the event count rate in right ascension and azimuth. The analysis is performed in three energy bins with boundaries at 4, 8, 16 and 32 EeV and two additional cumulative bins with energies above 8 and 32 EeV. The most significant signal is a dipolar modulation in right ascension for energies above 8 EeV, as previously reported, with statistical significance of 6.6σ. Additionally, we report the measurements of the angular power spectrum for the same energy bins with the same dataset.
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M3 - Conference article
AN - SCOPUS:85145006984
SN - 1824-8039
VL - 395
JO - Proceedings of Science
JF - Proceedings of Science
M1 - 335
T2 - 37th International Cosmic Ray Conference, ICRC 2021
Y2 - 12 July 2021 through 23 July 2021
ER -