LARGE-SCALE DISTRIBUTION OF ARRIVAL DIRECTIONS OF COSMIC RAYS DETECTED ABOVE 1018 eV AT THE PIERRE AUGER OBSERVATORY

THE PIERRE AUGER OBSERVATORY (PATRICIA HANSEN PERTENECE A LA COLABORACION)

The Astrophysical Journal

The American Astronomical Society

Año: 2012 vol. 34 p. 1 - 20

1538-4357

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above1018 eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declinationand right ascension in several energy ranges above 1018 eV, and reported in terms of dipolar and quadrupolarcoefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming thatany cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits ontheir amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 1018 eV fromstationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in alldirections.