Optical Identifications of 230 HIPASS Radio Sources

TL;DR

This paper reports the optical identification and characterization of 230 galaxies associated with HIPASS radio sources, revealing their properties, types, and the significance of low-surface-brightness galaxies in the sample.

Contribution

It provides new optical counterparts for HIPASS sources, including detailed morphological and photometric data, and analyzes their physical properties and stability criteria.

Findings

Low-surface-brightness galaxies are a significant fraction.

Median hydrogen mass-to-luminosity ratio is 2-3 times higher in faint galaxies.

Many objects are near the gravitational stability boundary.

Abstract

We present the coordinates, apparent magnitudes, and morphological types for 230 galaxies presumably identified with HIPASS (HI Parkes All-Sky Survey) sources. The new optical counterparts of the HIPASS sources follow the well-known statistical relationships between the hydrogen mass, luminosity, and type of galaxies. Low-surface-brightness galaxies constitute a significant fraction among these objects. The median value of the hydrogen mass-to-luminosity ratio for them is a factor of 2 or 3 higher than that for bright HIPASS galaxies, reaching $1.7 M_{\odot}/L_{\odot}$. A number of our objects are located near the boundary $\log(M_{HI}/L_B) = 0.2(M_B + 20)$ that defines the zone of gravitational stability of disk galaxies against large-scale star formation.