The Broad-band Optical Properties of Galaxies with Redshifts 0.0 < z < 0.2

TLDR: In this paper, the Sersic index was used to measure the radial profile shape of the galaxies in the Sloan Digital Sky Survey (SDSS), and the dependence of local galaxy density (smoothed on 8 h^{-1} Mpc scales) on all of these properties.

Abstract: Using photometry and spectroscopy of 144,609 galaxies from the Sloan Digital Sky Survey, we present bivariate distributions of pairs of seven galaxy properties: four optical colors, surface brightness, radial profile shape as measured by the Sersic index, and absolute magnitude. In addition, we present the dependence of local galaxy density (smoothed on 8 h^{-1} Mpc scales) on all of these properties. Several classic, well-known relations among galaxy properties are evident at extremely high signal-to-noise ratio: the color-color relations of galaxies, the color-magnitude relations, the magnitude-surface brightness relation, and the dependence of density on color and absolute magnitude. We show that most of the i-band luminosity density in the universe is in the absolute magnitude and surface brightness ranges used. Some of the relationships between parameters, in particular the color--magnitude relations, show stronger correlations for exponential galaxies and concentrated galaxies taken separately than for all galaxies taken together. We provide a simple set of fits of the dependence of galaxy properties on luminosity for these two sets of galaxies.