No CrossRef data available.
Published online by Cambridge University Press: 14 August 2015
The origin of the highest energy cosmic rays is unclear but the observation that many are seen to arrive from high Galactic latitudes supports the idea of Extragalactic sources. The characteristic features to be explained by any origin model are: the flattening of the energy spectrum above 1019eV and the apparent presence of a directional anisotropy which increases systematically with energy.