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.

Large-scale and multipolar anisotropies of cosmic rays detected at the Pierre Auger Observatory with energies above 4 EeV / De Almeida, R.M., Abreu, P., Aglietta, M., Albury, J.M., Allekotte, I., Almela, A., Alvarez-Muniz, J., Alves Batista, R., Anastasi, G.A., Anchordoqui, L., Andrada, B., Andringa, S., Aramo, C., Araujo Ferreira, P.R., Arteaga Velazquez, J.C., Asorey, H., Assis, P., Avila, G., Badescu, A.M., Bakalova, A., et al.. - In: POS PROCEEDINGS OF SCIENCE. - ISSN 1824-8039. - 395:(2022), pp. 1-12. (37th International cosmic ray conference, ICRC 2021 Berlin, Germany ) [10.22323/1.395.0335].

Large-scale and multipolar anisotropies of cosmic rays detected at the Pierre Auger Observatory with energies above 4 EeV

Mastrodicasa M.;
2022

Abstract

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.
2022
37th International cosmic ray conference, ICRC 2021
pierre auger observatory; cosmic rays; anisotropies
04 Pubblicazione in atti di convegno::04c Atto di convegno in rivista
Large-scale and multipolar anisotropies of cosmic rays detected at the Pierre Auger Observatory with energies above 4 EeV / De Almeida, R.M., Abreu, P., Aglietta, M., Albury, J.M., Allekotte, I., Almela, A., Alvarez-Muniz, J., Alves Batista, R., Anastasi, G.A., Anchordoqui, L., Andrada, B., Andringa, S., Aramo, C., Araujo Ferreira, P.R., Arteaga Velazquez, J.C., Asorey, H., Assis, P., Avila, G., Badescu, A.M., Bakalova, A., et al.. - In: POS PROCEEDINGS OF SCIENCE. - ISSN 1824-8039. - 395:(2022), pp. 1-12. (37th International cosmic ray conference, ICRC 2021 Berlin, Germany ) [10.22323/1.395.0335].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1752544
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