We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4EeV measured using the Pierre Auger Observatory. For the energy bins [4, 8] EeV and E>=8 EeV, the most significant signal is a dipolar modulation in R.A. at energies above 8 EeV, as previously reported. In this paper we further scrutinize the highest-energy bin by splitting it into three energy ranges. We find that the amplitude of the dipole increases with energy above 4 EeV. The growth can be fitted with a power law with index β=0.79±0.19. The directions of the dipoles are consistent with an extragalactic origin of these anisotropies at all the energies considered. Additionally, we have estimated the quadrupolar components of the anisotropy: they are not statistically significant. We discuss the results in the context of the predictions from different models for the distribution of ultrahigh-energy sources and cosmic magnetic fields.

Aab, A., Abreu, P., Aglietta, M., Albuquerque, I.F.M., Albury, J.M., Allekotte, I., et al. (2018). Large-scale Cosmic-Ray Anisotropies above 4 EeV Measured by the Pierre Auger Observatory. THE ASTROPHYSICAL JOURNAL, 868:4, 1-12 [10.3847/1538-4357/aae689].

Large-scale Cosmic-Ray Anisotropies above 4 EeV Measured by the Pierre Auger Observatory

Buscemi, M.;Marsella, G.;
2018-11-20

Abstract

We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4EeV measured using the Pierre Auger Observatory. For the energy bins [4, 8] EeV and E>=8 EeV, the most significant signal is a dipolar modulation in R.A. at energies above 8 EeV, as previously reported. In this paper we further scrutinize the highest-energy bin by splitting it into three energy ranges. We find that the amplitude of the dipole increases with energy above 4 EeV. The growth can be fitted with a power law with index β=0.79±0.19. The directions of the dipoles are consistent with an extragalactic origin of these anisotropies at all the energies considered. Additionally, we have estimated the quadrupolar components of the anisotropy: they are not statistically significant. We discuss the results in the context of the predictions from different models for the distribution of ultrahigh-energy sources and cosmic magnetic fields.
Settore FIS/01 - Fisica Sperimentale
https://iopscience.iop.org/article/10.3847/1538-4357/aae689
Aab, A., Abreu, P., Aglietta, M., Albuquerque, I.F.M., Albury, J.M., Allekotte, I., et al. (2018). Large-scale Cosmic-Ray Anisotropies above 4 EeV Measured by the Pierre Auger Observatory. THE ASTROPHYSICAL JOURNAL, 868:4, 1-12 [10.3847/1538-4357/aae689].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/547056
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