Ultra high energy cosmic rays: A review
arXiv:1011.1872
Abstract
We present the main results on the energy spectrum and composition of the highest energy cosmic rays of energy exceeding 10$^{18}$ eV obtained by the High Resolution Fly's Eye and the Southern Auger Observatory. The current results are somewhat contradictory and raise interesting questions about the origin and character of these particles.
12 pages, 6 figures, presented at the 2010 Vulcano workshop, Vulcano, Italy