Introduction to Astroparticle Physics: Cosmic Rays and Dark Matter

This lecture introduces astroparticle physics, focusing on cosmic rays and dark matter. It begins with a historical overview of cosmic ray research initiated by Viktor Hess, discussing the origins of cosmic rays and the development of gamma-ray and neutrino astronomy. The instructor explains the distribution of matter in the universe, emphasizing the homogeneity and isotropy of galaxies. The lecture covers the expansion of the universe, detailing the Hubble law and the dynamics of galaxy movement. The thermal history of the universe is explored, including the radiation-dominated era and the significance of the cosmic microwave background. The instructor discusses the concept of dark matter, tracing its origins to Fritz Zwicky's observations and the gravitational effects that suggest its existence. The lecture concludes with a discussion on neutrinos as potential dark matter candidates, their interactions, and the challenges in detecting them. Overall, the lecture provides a comprehensive overview of the fundamental concepts in astroparticle physics, linking historical discoveries to modern theories.