Large-scale cosmic-ray anisotropies above 4 EeV measured by the Pierre Auger Observatory

We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4 EeV 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 right ascension at energies above 8 EeV, as previously...

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Detalles Bibliográficos
Autores: Calcagni, Laura Randa, Dova, María Teresa, Hansen, Patricia María, Mariazzi, Analisa Gabriela, Sciutto, Sergio Juan, Tueros, Matías Jorge, Vergara Quispe, Indira Dajhana, Wahlberg, Hernán Pablo, The Pierre Auger Collaboration
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2018
País:Argentina
Institución:Universidad Nacional de La Plata
Repositorio:SEDICI (UNLP)
Idioma:inglés
OAI Identifier:oai:sedici.unlp.edu.ar:10915/125623
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/125623
Access Level:acceso abierto
Palabra clave:Física
Cosmic ray
Physics
Dipole
Amplitude
Pierre auger observatory
Context (language use)
Astrophysics
Cosmic cancer database
Right ascension
Anisotropy
Observatory
Auger
Astroparticle physics
Descripción
Sumario:We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4 EeV 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 right ascension 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.