Features of the energy spectrum of cosmic rays above 2.5× 10¹⁸ eV using the Pierre Auger Observatory

2020/08/31 by The Pierre Auger Collaboration, A. Aab, P. Abreu +380 · 2 citations
Physics and Astronomy · #astro-ph.HE

paper · pdf · doi:10.1103/physrevlett.125.121106

published as Phys. Rev. Lett. 125, 121106 (2020) · Published version; 2 figures, 1 table

arxiv created 2020/10/06 · arxiv updated 2020/10/07

Abstract

We 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× 10¹⁹ eV, the spectral index changes from 2.51 ± 0.03 \textrm (stat.) ± 0.05 \textrm (sys.) to 3.05 ± 0.05 \textrm (stat.)± 0.10\textrm (sys.), evolving to 5.1±0.3\textrm (stat.) ± 0.1\textrm (sys.) 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 \textrm (stat.) ± 1.40 \textrm (sys.) ) × 10⁵³~erg Mpc^-3.

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