Cosmic Rays around $10^{18}$eV: Implications of Contemporary Measurements on the Origin of the Ankle Feature

Abstract

The impressive power-law decay of the energy spectrum of cosmic rays over more than thirty orders of magnitude in intensity and for energies ranging over eleven decades between $\simeq 10^9$eV and $\simeq 10^{20}$eV is actually dotted with small irregularities. These irregularities are highly valuable for uncovering and understanding the modes of production and propagation of cosmic rays. They manifest themselves through changes in the spectral index characterising the observed power laws. One of these irregularities, known as the \textit{ankle}, is subject to conflicting interpretations for many years. If contemporary observations characterising it have shed new lights, they are still far from being able to deliver all the story. The purpose of this contribution is to give an overview of the physics of cosmic rays in the energy range where the transition between Galactic and extragalactic cosmic rays is expected to occur, and to deliver several lines of thought about the origin of the ankle.

Solicited review paper to appear in "Comptes Rendus: Physique"

References in corpus (6)

• The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment
• Spectrum of cosmic rays, produced in supernova remnants
• Ankle-like Feature in the Energy Spectrum of Light Elements of Cosmic Rays Observed with KASCADE-Grande
• Constraints on the origin of cosmic rays above $10^{18}$ eV from large scale anisotropy searches in data of the Pierre Auger Observatory
• Large scale distribution of arrival directions of cosmic rays detected above $10^{18}$ eV at the Pierre Auger Observatory
• The flux suppression at the highest energies

Cited by in corpus (6)

• Features of the energy spectrum of cosmic rays above $2.5\times 10^{18}$ eV using the Pierre Auger Observatory
• Constraining the sources of ultra-high-energy cosmic rays across and above the ankle with the spectrum and composition data measured at the Pierre Auger Observatory
• Diffusion of cosmic rays at EeV energies in inhomogeneous extragalactic magnetic fields
• Large Scale Anisotropy of Cosmic Rays and Directional Neutrino Signals from Galactic Sources
• Are EeV cosmic rays isotropic at intermediate scales?
• Ultra-high energy cosmic rays with UFA-15 source model in Bumblebee gravity theory