Features of the Energy Spectrum of Cosmic Rays above 2.5 × 10(18) eV Using the Pierre Auger Observatory Aab, A. Bueno Villar, Antonio 2.51 0.03ðstatÞ 0.05ðsystÞ to 3.05 0.05ðstatÞ 0.10ðsystÞ, evolving to 5.1 0.3ðstatÞ 0.1ðsystÞ 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 ½5.66 0.03ðstatÞ 1.40ðsystÞ × 1053 ergMpc−3 2020-10-30T07:07:56Z 2020-10-30T07:07:56Z 2020-09-16 journal article Aab, A., Abreu, P., Aglietta, M., Albury, J. M., Allekotte, I., Almela, A., ... & Anchordoqui, L. (2020). Features of the Energy Spectrum of Cosmic Rays above 2.5× 10 18 eV Using the Pierre Auger Observatory. Physical Review Letters, 125(12), 121106. [doi:10.1103/PhysRevLett.125.121106] http://hdl.handle.net/10481/63960 10.1103/PhysRevLett.125.121106 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access Atribución-NoComercial-SinDerivadas 3.0 España Amer Physical Soc