Aab, A.Álvarez Muñiz, JaimeParente Bermúdez, GonzaloZuccarello, F.2024-02-092024-02-092020-07-31Aab, A., Álvarez Muñiz, Jaime, Parente Bermúdez, Gonzalo, Zuccarello, F. et al (2020): Features of the Energy Spectrum of Cosmic Rays above 2.5 × 10 18     eV Using the Pierre Auger Observatory, en Phys. Rev. Lett. 125 (2020) 1211061079-7114http://hdl.handle.net/10347/32686We report a measurement of the energy spectrum of cosmic rays above 2.5×1018  eV based on 215 030 events. New results are presented: at about 1.3×1019eV, 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 5×1019e, 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. .engPublished by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOIhttp://creativecommons.org/licenses/by/4.0/Cosmic ray & astroparticle detectorsCosmic ray acelerationCosmic ray composition & spectraCosmic ray propagationCosmic ray sourcesjournal article10.1103/PhysRevLett.125.121106open access