Families of ellipsoidal stellar systems and the formation of dwarf elliptical galaxies

On the basis of measurements of core radii and central surface brightnesses of bulges and elliptical galaxies by means of CCD photometry, correlations between core parameters are derived and compared for the cases of ellipticals, bulges, dwarf spheroidal galaxies, dwarf irregular galaxies, and globular clusters. These data confirm the existence of well defined correlations between the core parameters of elliptical galaxies. The bulges of disk galaxies are basically similar to elliptical galaxies. A large discontinuity is noted between the parameter correlations for bright ellipticals and those for dwarf spheroidals, and it is found that a large difference exists between the parameter correlations for globular clusters and those for other ellipsoidal stellar systems.