A. Aab, Radboud Universiteit
P. Abreu, Instituto Superior Técnico
M. Aglietta, Istituto Nazionale di Fisica Nucleare, Sezione di Torino
I. F.M. Albuquerque, Universidade de São Paulo
J. M. Albury, The University of Adelaide
I. Allekotte, Centro Atomico Bariloche
A. Almela, Universidad Nacional de San Martín
J. Alvarez Castillo, Universidad Nacional Autónoma de México
J. Alvarez-Muñiz, Universidad de Santiago de Compostela
G. A. Anastasi, Gran Sasso Science Institute
L. Anchordoqui, Lehman College
B. Andrada, Universidad Nacional de San Martín
S. Andringa, Instituto Superior Técnico
C. Aramo, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
H. Asorey, Centro Atomico Bariloche
P. Assis, Instituto Superior Técnico
G. Avila, Pierre Auger Observatory
A. M. Badescu, University Politehnica of Bucharest
A. Balaceanu, Horia Hulubei National Institute of Physics and Nuclear Engineering
F. Barbato, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
R. J.Barreira Luz, Instituto Superior Técnico
S. Baur, Karlsruher Institut für Technologie
K. H. Becker, Bergische Universität Wuppertal
J. A. Bellido, The University of Adelaide
C. Berat, Universite Grenoble Alpes
M. E. Bertaina, Istituto Nazionale di Fisica Nucleare, Sezione di Torino
X. Bertou, Centro Atomico Bariloche
P. L. Biermann, Max Planck Institute for Radio Astronomy
J. Biteau, Institut de Physique Nucléaire d’Orsay
S. G. Blaess, The University of Adelaide
A. Blanco, Instituto Superior Técnico
J. Blazek, Institute of Physics of the Czech Academy of Sciences
C. Bleve, Istituto Nazionale di Fisica Nucleare, Sezione di Lecce

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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 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.

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Astrophysical Journal