Introduction

This talk starts with a brief and highly selective review of the theory of galaxy formation, with a focus on the importance of gas processes. It is then argued that most of the gas in dwarf protogalaxies will be self-gravitating, so that gas processes play a major role in determining the visible structure of dwarf galaxies.

Section 2 discusses the arguments for a dark matter dominated hierarchical collapse. While the dominant form of matter is dark, it is argued that the primordial gas fraction must be at least 20 percent to account for the high gas fractions in clusters. Section 3 outlines why fully numerical models for galaxy formation may not be the most reliable. It is argued in section 4 that the early collapse of, at least, the larger protodwarf galaxies leads to major starbursts and outflows. Finally, in section 5, it is shown that the disks of most galaxies are largely self-gravitating. In particular, this means that we should not expect gravitating matter in the region of the disk to be well-fitted by the universal dark matter profile of Navarro, Frenk & White (1997 -- NFW), which models collisionless galaxy halos.

© Copyright Astronomical Society of Australia 1997