LEARNING OUTCOMES
The student will be able to calculate the relaxation and dynamical timescales for galaxies. The student will be able to calculate the gravitational potential for spherical
and flattened systems. The student will understand the basic principles of direct summation codes, tree codes and particle-mesh codes used to perform numerical
galaxy formation simulations. The student will be able to describe the orbits of stars in spherical, axisymmetric and simple non-axisymmetric potentials. The student will be able to use basic integrators. The student will understand how the Boltzmann and Jeans equations can be used in galaxy dynamics. The student will be able to derive the tensor virial theorem. The study will be able to understand the stability of collisionless systems. The student will
understand the basics of relaxation processes in galaxies and understand the thermodynamics of self-gravitating systems. The student will be able to derive the formula
for dynamical friction and understand its application. The student will understand the importance of galaxy mergers for galaxy evolution.
CONTENT
Galactic dynamics is an integral part of modern theoretical astrophysics. The course follows the outline of the second edition of the classic text "Galactic Dynamics" by Binney & Tremaine (2008). We begin with a general introduction to galactic dynamics followed by a discussion of relaxation and dynamical timescales. After this we discuss potential theory, how to compute the gravitational potential of galaxies and how to describe galaxies using spherical and flattened density distributions. This is followed by a discussion of Poisson solvers. Then orbit theory is discussed, specifically what kinds of orbits are possible in galaxies described by a spherically symmetric, or an axially symmetric potential. Orbits in simply non-axisymmetric potentials will also be discussed.
We continue with a discussion of distribution functions and the equilibria of collisionless systems, and derive the collisionless Boltzmann equation. We then discuss the Jeans and virial equations and with the help of them detect black holes and dark matter haloes in galaxies using observations of the kinematics of their stars. This is followed by a discussion of the stability of collisionless systems. Next we discuss disk dynamics and spiral structure, followed by a discussion on kinetic theory and the thermodynamics of self-gravitating systems. We end the course with a discussion on dynamical friction and its applications and describe the related concepts of galaxy interactions and mergers.
