Measurement of the Cosmic Ray Spectrum Above 4×1018 EV Using Inclined Events Detected with the Pierre Auger Observatory

Download or read book Measurement of the Cosmic Ray Spectrum Above 4×1018 EV Using Inclined Events Detected with the Pierre Auger Observatory written by and published by . This book was released on 2015 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the cosmic-ray spectrum for energies exceeding 4×1018 eV is presented, which is based on the analysis of showers with zenith angles greater than 60° detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×1018 eV, the ``ankle'', the flux can be described by a power law E-[gamma] with index [gamma]=2.70 ± 0.02 (stat) ± 0.1 (sys) followed by a smooth suppression region. For the energy (Es) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25 (stat)+1.0-1.2 (sys))×1019 eV.