A review of action estimation methods for galactic dynamics

Understand

We review the available methods for estimating actions, angles and frequencies of orbits in both axisymmetric and triaxial potentials.

• The methods are separated into two classes.
• Unless an orbit has been trapped by a resonance, convergent, or iterative, methods are able to recover the actions to arbitrarily high accuracy given sufficient computing time.
• Faster non-convergent methods rely on the potential being sufficiently close to a separable potential and the accuracy of the action estimate cannot be improved through further computation.