| In this thesis I present analyses of optical and X-ray data of early-type galaxies in nearby rich clusters as part of the NOAO Fundamental Plane Survey. Spectroscopic parameters, including linestrengths and velocity dispersions are measured for ∼4000 red-sequence galaxies and are found to be in good agreement with those in other surveys. We find gradients of the linestrength residuals with cluster radius, and while many clusters exhibit expected linestrength-radius relations, most of these gradients are not statistically significant. Several line indices, including Mgb, iron lines and Balmer lines, have significant correlation with velocity dispersion, sigma. These linestrength-sigma relations are used to derive global trends of age, metallicity, and alpha-enhancement with galaxy mass. We find that more massive galaxies are older, more metal-rich, and more alpha-enhanced than less massive galaxies; specifically, the relations are alpha/Fe ∝ sigma0.31+/-0.06, Z/H ∝ sigma 0.53+/-0.08, and age ∝ sigma05.9+/-0.13. These results are in good agreement with intermediate-redshift observations but disagree with semi-analytic galaxy formation models. Age, metallicity, and alpha-enhancement are also found to decrease slightly with cluster radius. Virial masses are calculated for all of our clusters and are found to be in good agreement with previous estimates. The variance of our age and metallicity gradients with galaxy mass is not found to vary significantly with cluster mass. Finally, Chandra X-ray data of 21 of our clusters is used to investigate the mechanism of X-ray emission in early-type galaxies. Based on our Lx/Lb ratios, low-mass X-ray binaries appear to be the sole source of emission in most of the ∼1000 galaxies of our sample; thus, the hot gaseous halos around these galaxies have likely been stripped. |
