Correlations among the properties of galaxies found in a blind HI survey, which also have SDSS optical data

Abstract

We have used the Parkes Multibeam system and the Sloan Digital Sky Survey (SDSS) to assemble a sample of 195 galaxies selected originally from their HI signature to avoid biases against unevolved or low surface brightness objects. For each source 9 intrinsic properties are measured homogeneously, as well as inclination and an optical spectrum. The sample, which should be almost entirely free of either misidentification or confusion, includes a wide diversity of galaxies ranging from inchoate, low surface brightness dwarfs to giant spirals. Despite this diversity there are 5 clear correlations among their properties. They include a common dynamical mass-to-light ratio within their optical radii, a correlation between surface-brightness and Luminosity and a common HI surface-density. Such correlation should provide strong constrains on models of galaxy formation and evolution.

17 pages, 22 figures, submitted to MNRAS