EVIDENCE FROM INTRINSIC SHAPES FOR 2 FAMILIES OF ELLIPTIC GALAXIES

Bright elliptical galaxies have a markedly different distribution of H ubble types than faint ellipticals; the division occurs near M(B)=-20 and bright ellipticals are rounder on average. The Hubble types of gal axies in both groups are narrowly clustered, around E1.5 in the case o f the bright galaxies and around E3 for the fainter ones. The Hubble-t ype distribution of the faint ellipticals is consistent with oblate sy mmetry, but the oblate hypothesis fails for the bright ellipticals. Ho wever a distribution of triaxial intrinsic shapes can successfully rep roduce the apparent shape data for either group. The distribution of i ntrinsic, short-to-long axis ratios is peaked around 0.75 for bright g alaxies and 0.65 for faint galaxies. Our results provide further evide nce that elliptical galaxies should be divided into two, morphological ly distinct families. (C) 1996 American Astronomical Society.