INVESTIGADORES
BERTOU Xavier Pierre Louis
artículos
Título:
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory
Autor/es:
THE PIERRE AUGER COLLABORATION; XAVIER BERTOU
Revista:
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
Editorial:
IOP PUBLISHING LTD
Referencias:
Lugar: Londres; Año: 2017
ISSN:
1475-7516
Resumen:
We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80(o) and energies in excess of 4 EeV (4 × 10(18) eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured, while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding p-values obtained after accounting for searches blindly performed at several angular scales, are 1.3 × 10(−)(5) in the case of the angular power spectrum, and 2.5 × 10(−)(3) in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.