2014/03/21 by Olivier Deligny · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Gamma-ray bursts and supernovae #astro-ph.HE
paper · pdf · doi:10.1016/j.crhy.2014.02.009
published as C.R. Physique 15 (2014) 367-375 · Solicited review paper to appear in "Comptes Rendus: Physique"
arxiv created 2014/03/21 · openalex publication_date 2014/03/21 · arxiv updated 2014/07/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≃</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> </mml:msup> <mml:mtext>eV</mml:mtext> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≃</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>20</mml:mn> </mml:mrow> </mml:msup> <mml:mtext>eV</mml:mtext> </mml:math> 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 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.