The spectrum of high-energy cosmic rays measured with KASCADE-Grande

TL;DR

This paper presents the detailed energy spectrum of high-energy cosmic rays measured by KASCADE-Grande, revealing spectral features that challenge the simple power-law model and suggest a transition from galactic to extragalactic sources.

Contribution

It provides the first detailed measurement of the cosmic ray spectrum between 10^16 and 10^18 eV, highlighting spectral features indicating complex astrophysical processes.

Findings

Spectrum shows a hardening at ~2x10^16 eV

Spectrum steepens at ~8x10^16 eV

Challenges the single power-law assumption

Abstract

The energy spectrum of cosmic rays between 10**16 eV and 10**18 eV, derived from measurements of the shower size (total number of charged particles) and the total muon number of extensive air showers by the KASCADE-Grande experiment, is described. The resulting all-particle energy spectrum exhibits strong hints for a hardening of the spectrum at approximately 2x10**16 eV and a significant steepening at c. 8x10**16 eV. These observations challenge the view that the spectrum is a single power law between knee and ankle. Possible scenarios generating such features are discussed in terms of astrophysical processes that may explain the transition region from galactic to extragalactic origin of cosmic rays.