School of modern astrophysics

Radiative processes in (high-energy) astrophysics

Juri Poutanen (Tuorla Observatory, Finland)

Lecture 1. General description.

Review of most important radiative processes in high-energy astrophysics.
Kinetic equations for electrons and photons.
Radiative transfer equation. Emission and absorption coefficients. Simple solutions.

Lecture 2. Cyclo-synchrotron radiation.

Larmor formula. Cyclotron radiation. Radiated power.
Emission of relativistic particles. Cooling time. Spectrum of radiation from monoenergetic and from a power-law distribution of electrons.
Synchrotron absorption. Thermalization by synchrotron self-absorption.

Lectures 3. Compton scattering.

Thomson scattering. Inverse Compton scattering. Radiative power.
Spectrum of emission. Non-relativistic Compton scattering, Kompaneets equation.
Comptonization. Applications to accreting black holes and neutron stars.
Klein-Nishina effect. Electron cooling rate. Synchrotron self-Compton mechanism.
Applications to active galaxies and gamma-ray bursts.

Lecture 4. Pair production.

Photon-photon pair production cross-section. Pair cascades.
Photon breeding. GeV breaks in blazars.

Problems to solve