Features of the Energy Spectrum of Cosmic Rays above 2.5 × 1018 eV Using the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2020 vol. 125 p. 121106 - 121116

0031-9007

We report a measurement of the energy spectrum of cosmic rays above 2.5 × 1018 eV based on215 030 events. New results are presented: at about 1.3 × 1019 eV, the spectral index changes from 2.51 +- 0.03(stat) +- 0.05(syst) to 3.05 +- 0.05(stat) +- 0.10(syst), evolving to 5.1 +- 0.3(stat) +- 0.1(syst) beyond 5 × 1019 eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5×1018 eV is [5.66 +- 0.03(stat) +- 1.40(syst)] × 1053 ergMpc−3.