Declination dependence of the cosmic-ray flux at extreme energies

Abstract

We study the large-scale distribution of the arrival directions of the highest energy cosmic rays observed by various experiments. Despite clearly insufficient statistics, we find a deficit of cosmic rays at energies higher than 10^{20} eV from a large part of the sky around the celestial North Pole. We speculate on possible explanations of this feature.

Comments: 5 pages, 4 figures; v2: 11 pages, 4 figures, title changed (to avoid confusion with the Southern hemisphere), analysis extended, more data included, results unchanged; to be published in JCAP