The Shape of Dark Matter Haloes, I. HI Observations of Edge-on Galaxies

TL;DR

This study uses HI observations of eight edge-on galaxies to analyze their neutral hydrogen distribution, revealing consistent surface brightness temperatures likely due to self-absorption, emphasizing the need for this consideration in future analyses.

Contribution

It provides detailed HI observations of edge-on galaxies and highlights the importance of accounting for self-absorption in their surface brightness profiles.

Findings

All galaxies have similar maximum surface brightness temperatures.

Self-absorption is identified as the main cause of uniform brightness.

Most galaxies are well-resolved radially, some vertically.

Abstract

We present neutral hydrogen observations for a sample of eight nearby, late-type, edge-on galaxies. All of the galaxies have been well resolved in the radial direction, while six have also been well resolved in the vertical direction. We find that each of the galaxies has approximately the same maximum surface brightness temperature throughout its disc. We argue that self-absorption is the main cause of this phenomenon and that subsequent decompositions will require a treatment of this.