Key points are not available for this paper at this time.
Fe and Mg indices from two homogenous collections of nuclear elliptical galaxy spectra are compared with model indices. In the average giant elliptical, the Mg/Fe ratio exceeds that of the most metal-rich stars in the solar neighborhood by ~0.2-0.3 dex, with a large spread about this mean. This result implies a variable "enrichment effectiveness" of Type II supernovae (SNs) compared with Type Ia SNs in the evolution of ellipticals, caused perhaps by differences in star formation time scales, the initial mass function, or the amount of Fe versus Mg ejected in galactic winds.
Worthey et al. (Thu,) studied this question.