2. High-energy Astrophysics and Astroparticle Physics

High Energy Astrophysics can be studied through processes that involve electrons and protons/nuclei. The first part of these lectures focuses on processes induced by electrons, which lead to electromagnetic emission from keV to GeV/TeV energies from populations of Galactic and extra-galactic sources. Results from X-ray and gamma-ray space telescopes will be discussed. The second part focuses on the production and acceleration of protons and nuclei and the problem of missing antimatter in the Universe. The method of multimessenger observations of astrophysical objects in the framework of space experiments is finally presented.

The learning objectives are:

• Emission mechanisms: blackbody/bremsstrahlung/synchrotron/Compton scattering and Inverse Compton scattering. Eddington limit and accretion discs;
• Compact sources: X-ray binaries, Active Galactic Nuclei and accreting supermassive black holes, Gamma Ray Bursts
• Extended sources: Clusters of galaxies; the Galactic Center
• Particles and antiparticles in the Universe observed from satellites
• Cosmic rays and the connection with supernovae
• Production of nuclei in the periodic table of elements from different processes
• Multimessenger observations of gravitational waves, gamma-rays and other electromagnetic radiations.