Authors: Alister W. Graham
Abstract: This article reviews the popular reasons for the belief that dwarf elliptical galaxies and (ordinary) elliptical galaxies are distinct and separate species. They include: light-profile shape (or similarly image concentration); the magnitude-central surface brightness diagram; the magnitude-effective surface brightness diagram (or similarly the magnitude-effective radius diagram); and the Fundamental Plane. It is shown how a continuous trend between luminosity and a) light-profile shape, and b) central surface brightness (until the onest of core formation at MB ~ -20.5 mag, results in a unification of the dwarf elliptical and (ordinary) elliptical galaxies. Neither the above four reasons, nor the luminosity function (at least in the Virgo cluster) provide evidence for a division at MB = -18 mag between the dwarf elliptical and (ordinary) elliptical galaxies. Instead, they appear to be continuous extensions of each other.