AA53CH06-Grenier ARI 29 July 2015 12:16 The Nine Lives of Cosmic Rays in Galaxies Isabelle A. Grenier,1 John H. Black,2 and Andrew W. Strong3 1Laboratoire AIM Paris-Saclay, CEA/Irfu, CNRS, Universite´ Paris Diderot, F-91191 Gif-sur-Yvette Cedex, France; email:
[email protected] 2Department of Earth & Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden; email:
[email protected] 3Max-Planck-Institut fur¨ extraterrestrische Physik, 85741 Garching, Germany; email:
[email protected] Annu. Rev. Astron. Astrophys. 2015. 53:199–246 Keywords First published online as a Review in Advance on γ rays, interstellar medium, interstellar chemistry, dust, superbubbles June 18, 2015 The Annual Review of Astronomy and Astrophysics is Abstract online at astro.annualreviews.org Cosmic-ray astrophysics has advanced rapidly in recent years, and its impact This article’s doi: on other astronomical disciplines has broadened. Many new experiments 10.1146/annurev-astro-082214-122457 measuring these particles, both directly in the atmosphere or space and in- Annu. Rev. Astro. Astrophys. 2015.53:199-246. Downloaded from www.annualreviews.org Access provided by University of Maryland - College Park on 08/24/15. For personal use only. Copyright c 2015 by Annual Reviews. directly via γ rays and synchrotron radiation, have widened the range and All rights reserved quality of the information available on their origin, propagation, and inter- actions. The impact of low-energy cosmic rays on interstellar chemistry is a fast-developing topic, including the propagation of these particles into the clouds in which the chemistry occurs.