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

TL;DR

This study combines HI and SDSS data to analyze 195 galaxies, revealing five key correlations among their properties that inform galaxy formation and evolution models.

Contribution

It provides a homogeneous analysis of galaxy properties from HI and optical data, identifying new correlations across diverse galaxy types.

Findings

Common dynamical mass-to-light ratio within optical radii

Correlation between surface brightness and luminosity

Shared HI surface density among galaxies

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.