The energy spectrum of cosmic rays beyond the turn-down around 1017 eV as measured with the surface detector of the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

The European Physical Journal C

Springer

Año: 2021 vol. 81 p. 966 - 990

We present a measurement of the cosmic-rayspectrum above 100PeV using the part of the surface detectorof the Pierre Auger Observatory that has a spacing of 750 m.An inflection of the spectrum is observed, confirming thepresence of the so-called second-knee feature. The spectrumis then combined with that of the 1500m array to produce asingle measurement of the flux, linking this spectral featurewith the three additional breaks at the highest energies. Thecombined spectrum, with an energy scale set calorimetricallyvia fluorescence telescopes and using a single detector type,results in the most statistically and systematically precisemeasurement of spectral breaks yet obtained. These measurementsare critical for furthering our understanding of thehighest energy cosmic rays.