International School of Cosmic Ray Astrophysics

16^th  Course: "Gamma Ray and Cosmic Ray Astrophysics: From below GeV to beyond EeV Energies"

 5-12 July 2008
Ettore Majorana Centre
Erice, Sicily, Italy

Topic: Evidence for Cosmic-Ray Origin in Galactic OB Associations
Lecturer: Martin Israel

There are regions of our Galaxy populated by massive, relatively short-lived, stars of spectral classes O and B. These OB associations are where most core-collapse supernovas occur. Deviations of the composition of cosmic rays from that of the ambient material of our Solar System point to cosmic-ray origin in such regions, where the interstellar material is enriched by the material flowing out of such massive stars. Evidence for this origin in OB associations comes from the isotopic composition of cosmic-ray neon, iron, and other elements, as well as the elemental abundances of carbon, nitrogen, and oxygen and of rare elements heavier than iron.