The cosmic ray energy spectrum measured using the Pierre Auger Observatory

Abstract

We present an update of the cosmic ray energy spectrum measured from 3×1017 eV to over 1020 eV at the Pierre Auger Observatory. This energy range is covered by combining data from the surface detector (subdividing the events into a vertical and a horizontal data set), from a denser array of stations and from hybrid events simultaneously recorded by the surface and the fluorescence detectors. Data collected to date, with a total exposure exceeding 67, 000 km2 sr yr, rely on the energy scale provided by the fluorescence detector. The spectral features, and the impact of systematic uncertainties on their significance, are discussed in detail.