Potential-density pairs for galaxies

A new class of triaxial potential-density pairs, which consists of an infinite number of families, is presented. The first family corresponds to density distributions that decrease not faster than r-2 at large radii r, and hence is relevant for galaxies with massive haloes. The second family is the family of Staeckel potentials, studied elsewhere. The associated density distributions fall off as r-4 or slower. The mass models belonging to the higher order families may have steeper density profiles. The whole class is 'generated' by a set of exactly ellipsoidal density distributions, analogous to the Ferrers ellipsoids. Many properties of the models resemble closely those of the Staeckel models. (author)