Features of the energy spectrum of cosmic rays above 2.5 x 10^18 eV using the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION (VER M. PLATINO EN PUBLICACIÓN); MANUEL PLATINO

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2020 vol. 125

0031-9007

We report a measurement of the energy spectrum of cosmic rays above 2.5×10^18 eV based on 215,030 events. New results are presented: at about 1.3×10^19 eV, the spectral index changes from 2.51±0.03 (stat.)±0.05 (sys.) to 3.05±0.05 (stat.)±0.10 (sys.), evolving to 5.1±0.3 (stat.)±0.1 (sys.) beyond 5×10^19 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 5×10^18 eV is (5.66±0.03 (stat.)±1.40 (sys.))×10^53 erg Mpc^−3.