Structural and dynamical forms of elliptical and dwarf galaxies

This review discusses two intriguing problems posed by observations of early-type galaxies: First, the existence of a so-called fundamental plane of elliptical galaxies and its thickness impose strong constraints on their global dynamical structures, stellar populations, and the relation of dark to visible matter in them. Second, the prevalence of extreme core-halo structures among the nucleated dwarf galaxies. Finally, some general remarks are made about the standard density forms of galactic subsystems, including dark halos. These empirical findings provide strong constraints and valuable clues for models of galaxy formation. They may point towards the existence of preferred dynamical structures in galaxies, perhaps globally stable or maximum entropy states, reached through different formative histories.