Systematic differences between the field and cluster ellipticals

Extract

We applied multivariate statistical techniques to study the possible systematic differences between the field and cluster ellipticals, in the framework of the fundamental plane (FP) of elliptical galaxies on the samples of elliptical galaxies from the general field and loose groups, and from rich clusters. The data set used here are the ellipticals from the “7 Samurai” (Burstein et al. 1987; Davies et al. 1987), limited to cz < 6000 km/s. There are 55 galaxies in the cluster sample (mostly from the Coma and Virgo clusters), and 57 galaxies in the field sample, which may include galaxies in loose and poor groups. We have also used the data set from Djorgovski & Davis (1987), with very similar results.