isochrone_to_aa¶
-
gala.dynamics.
isochrone_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.
Note
This function is included as a method of the
IsochronePotential
and it is recommended to callphase_space()
instead.Parameters: w :
gala.dynamics.CartesianPhaseSpacePosition
,gala.dynamics.CartesianOrbit
potential :
gala.potential.IsochronePotential
, dictAn 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: actions :
numpy.ndarray
An array of actions computed from the input positions and velocities.
angles :
numpy.ndarray
An array of angles computed from the input positions and velocities.
freqs :
numpy.ndarray
An array of frequencies computed from the input positions and velocities.