The process of modeling elliptical galaxies (or constructing models of interest for elliptical galaxies) can be interpreted in very different ways depending on the goals we have in mind. Some of this variety of approaches was already implicit in Chapter 14 in the context of the modeling of galaxy disks. Theremuch of the emphasis was on the construction of realistic basic states as a prerequisite for an appropriate stability analysis; thus the discussion focused on a number of physical arguments (see especially Section 14.4) aimed at identifying general and flexible classes of models with realistic properties. The main goal was to produce a sound physical basis for a dynamical study of some outstanding morphological aspects of galaxy disks, especially spiral structure. Nevertheless, in that chapter we found it instructive to describe a few different models; for example, in Section 14.1 we took a close look at the vertical equilibrium of the disk, which might have been explored even further if we had in mind a deeper analysis of the problem of dark matter in the solar neighborhood. In addition, we also introduced a few exact models (Section 14.3) that offer useful analytical tools and clarify some of the issues related to the support of equilibrium configurations.

There are a number of important dynamical questions related to elliptical galaxies:

For bright elliptical galaxies, why is there basically one universal luminosity profile (the R1/4 law) on the global scale?

What is such universality telling us about the formation and the long-term evolution of these stellar systems?