Features of the Energy Spectrum of Cosmic Rays above 2.5 x 10^18 eV Using the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION (A. AAB, ..., A.D. SUPANITSKY, ...)

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

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

0031-9007

We report a measurement of the energy spectrum of cosmic rays above 2.5x10^18 eV based on 215 030 events. New results are presented: at about 1.3x10^19 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 5x10^19 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 5x10^18 eV is [5.66+-0.03(stat)+-1.40(syst)]x10^53 erg Mpc^−3.