Lecture
This lecture introduces the concept of photons as carriers of energy, explaining their relationship with frequency and wavelength. It covers how energies are measured in astrophysics, including energy fluxes and radiation pressure. The lecture also discusses the energy distribution of photons, distinguishing between continuous and discrete spectra, and provides examples of stellar spectra. Additionally, it explores black body radiation, Compton diffusion, bremsstrahlung, and synchrotron radiation, highlighting their significance in astrophysical processes.