Galaxy image processing and morphological modeling: Applications to understanding galaxy formation and evolution

This dissertation presents improvements in methods of processing and analyzing data from optical telescopes. With my collaborators, I have developed software tools which have been successfully used on data from the Sloan Digital Sky Survey (SDSS) and the Hubble Space Telescope (HST). I have participated in applying this software in studies of the properties of galaxies. These studies have led to advances in the understanding of early-type galaxies, including some of the brightest and most massive galaxies in the Universe. The software package we have developed, called GALM ORPH, has been made publicly available to enable other researchers to use it in their studies.;We present the models and the methods used by GALM ORPH to model the light distribution in images of galaxies. We used simulations to test the effects of errors which come from noise, background light, blending of sources, and incorrect model selection. We present a method which effectively chooses the best class of model for a given data image.;We use GALMORPH in various observational studies of galaxies. With 50,000 early-type galaxies, we measure the correlations of size, luminosity, and velocity dispersion. Our precision measurements of all these quantities provides a useful benchmark for theoretical models of galaxy formation and evolution. We study the brightest galaxies in clusters (BCGs) to see how their properties differ from the bulk population of galaxies. We find a qualitative agreement between the observed scaling relations of BCGs and the prediction of models which incorporate merger-driven growth with quenched star formation in more massive halos. We present the first observational limit of the highest velocity dispersion using the large galaxy sample of the Sloan Digital Sky Survey, ruling out line-of-sight superpositions using the Hubble Space Telescope. We also present a method for measuring the optical light from images of galaxies which contain active galactic nuclei (AGN), and a study of tidal features in merging galaxies.