Triaxial Galaxy Models With Separable Potentials

B. Terzic, C. Hunter, T. de Zeeuw

We present a numerical scheme for the construction of three-integral phase-space distribution functions (DF) for triaxial galaxy models with a gravitational potential of Stackel form, and an arbitrary triaxial luminous density distribution. The intrinsic velocity moments are obtained with little extra effort. The orbits all have three independent integrals of motion and form four different families, the inner and outer long axis tubes, short axis tubes and boxes.

Our models are not unique. Our method of construction begins with a choice of how to split the density between the inner and outer long axis tubes on a plane in which these are the only orbital families. Also, the dependence of the distribution function of each of the tube families on the radial action is chosen in advance. Once these choices have been made, no other arbitrariness remains.

The numerical scheme presented takes the chosen density, computes the thin-tube distribution functions (maximum streaming) and 'thickens' them according to their prescribed radial dependence. The numerical scheme represents a triaxial generalization of the scheme implemented by Robijn & de Zeeuw for oblate models.