isochrone_xv_to_aa

gala.dynamics.isochrone_xv_to_aa(w, potential)[source]

Transform the input cartesian position and velocity to action-angle coordinates in the Isochrone potential. See Section 3.5.2 in Binney & Tremaine (2008), and be aware of the errata entry for Eq. 3.225.

This transformation is analytic and can be used as a “toy potential” in the Sanders & Binney (2014) formalism for computing action-angle coordinates in any potential.

Parameters
wgala.dynamics.PhaseSpacePosition, gala.dynamics.Orbit
potentialgala.potential.IsochronePotential, dict

An instance of the potential to use for computing the transformation to angle-action coordinates. Or, a dictionary of parameters used to define an gala.potential.IsochronePotential instance.

Returns
actionsQuantity

Actions computed from the input positions and velocities.

anglesQuantity

Angles computed from the input positions and velocities.

freqsQuantity

Frequencies computed from the input positions and velocities.