Lecture 40

Cosmic-Ray Fossils I: Lithium, Beryllium, and Boron

• ⁶LiBeB: orphans of nucleosynthesis
• Hint: cosmic-ray vs solar abundances
• cosmic ray LiBeB production
  • spallation
  • fusion
• solar LiBeB explained

Cosmic-Ray Fossils II: Diffuse Gamma Rays

• History: the gamma-ray sky emerges
  • OSO-3: Kraushaar et al 1972
  • SAS-2: Fichtel et al 1975
  • EGRET
  • Fermi: sky, movie
    fresh Galactic diffuse spectrum (Abdo et al 2009)
• Basic physics
  • emission mechanisms
  • radiation transfer
• guaranteed sources: Galactic and extragalactic
  
  • Hint: the sky in 21 cm (atomic H), CO (molecular H), and H alpha (ionized H)
  • active galactic nuclei: blazars
    e.g., 3C279 and 3C273
    sketch of unification scheme
  • star-forming galaxies