Origin of cosmic rays of the highest energies

Abstract

An analysis is made of the current status of the measurement of the energy spectrum and directional anisotropy of cosmic rays of the highest energy, i.e. above about 10¹⁸ eV. All the measurements are consistent with cosmic rays below 10¹⁹ eV being largely of Galactic origin and having a small excess in the general direction of the Galactic plane, with those of higher energy having come from extragalactic sources. There is evidence that the extra-galactic particles arrive preferentially from the general direction of the centre of the local supercluster and perhaps from directions towards the Galactic South Pole. The latter result is not understood.