: Explaining the origin and stability of spiral structures through density wave theory.
At its heart, the field treats galaxies as many-body systems where stars interact primarily through a smooth gravitational potential. Key areas of study include:
: Analyzing how individual stars move within these potentials, including orbits in axisymmetric and triaxial galaxies. Galactic Dynamics
: Understanding systems where individual stellar encounters are rare enough to be ignored. This uses the Collisionless Boltzmann Equation and Jeans Equations to describe equilibrium.
The field is largely defined by a few foundational textbooks and modern interactive guides: Galactic Dynamics: Second Edition - Google Books : Explaining the origin and stability of spiral
: Calculating the gravitational potential generated by various mass distributions, such as disks, bulges, and dark matter halos.
: Studying processes like dynamical friction (the "drag" on massive objects moving through a sea of stars) and violent relaxation . Essential Resources : Studying processes like dynamical friction (the "drag"
is the branch of astrophysics that uses the tools of theoretical physics to explain the motion and arrangement of stars, gas, and dark matter within galaxies. It primarily focuses on understanding how gravitational forces shape galactic structures—like spiral arms and central bulges—over billions of years. Core Theoretical Concepts