Pierre Auger Observatory 2003+: detection of >10^18 eV cosmic-rays via giant air-showers; spectrum cutoff at GZK (Greisen-Zatsepin-Kuzmin) limit ~5 x 10^19 eV.
Pierre Auger Observatory 2003+: detection of >10^18 eV cosmic-rays via giant air-showers; spectrum cutoff at GZK (Greisen-Zatsepin-Kuzmin) limit ~5 x 10^19 eV.