ABSORPTION-LINE SPECTRA OF ELLIPTIC GALAXIES AND THEIR RELATION TO ELLIPTIC FORMATION

Recent spectral data strongly suggest that elliptical galaxies represent at least a two- and probably a three-parameter sequence: light-element abundance, iron-peak abundance, and probably age. These data are discussed in the context of new ideas about elliptical formation, including hierarchical clustering, merger-caused starbursts, and a variable IMF. Non-solar abundance ratios set important constraints on elliptical formation.