The nature of E and SO galaxies

Differences and similarities of E and SO galaxies have been studied based on CCD surface photometry in Gunn r for a magnitude limited sample of E and SO galaxies in the Coma cluster. Spectroscopy is available for about half the sample. Our analysis of the relative disk luminosities, the Fundamental Plane, and the Mg-2-log sigma relation implies that E and SO galaxies fainter than M(BT) = -22(m) belong to the same class of galaxies, instead of two separate classes.