Ultra–High Energy Cosmic Rays: Are They Isotropic?

Abstract
From the analysis of Akeno Giant Air Shower Array (AGASA) data above 4 × 1019 eV, we show that the ultra-high energy cosmic ray flux is neither purely isotropic nor reflects the expected anisotropy from a pure source distribution that maps large-scale structure in the local universe. The arrival distribution seems to be the result of a mixture of fluxes (e.g., dark matter halo plus large-scale structure) or the superposition of direct and diffuse radiation field components, respectively. Another viable option is an arbitrary extragalactic flux reprocessed by a magnetized galactic wind model, as recently proposed in the literature.
All Related Versions