Institute of Astronomy

Dwarf Galaxies

Dwarf galaxies are the smallest objects in the universe which appear to contain vast amounts of dark or "missing" matter. The presence of this dark matter is inferred from the difference between the mass of these galaxies as measured by adding up all of their visible light, and the mass determined from dynamical measurements.

They are particularly interesting objects since, in our current understanding of galaxy formation, galaxies form hierarchically from the bottom-up. Thus dwarf galaxies may be the left over pieces from the formation of larger galaxies such as our own galaxy, the Milky Way. If this is the case then the shape and structural properties of these galaxies should be able to tell us much about what the conditions in the early universe were like. Their number and distribution should be able to provide observational tests for cosmological theories and the distribution of dark matter within these galaxies should be able to tell us something about what dark matter actually is.

However, before any such conclusions can be drawn from observations of these, tiniest of galaxies, we need to understand how they formed. This is because the properties we observe for these galaxies today may be telling us more about the processes and environment within which these galaxies formed than the initial conditions of the early universe.

Our programme here at the IoA involves every stage in the above process: making detailed measurements of the nearby dwarf galaxies, searching for and classifying new dwarf galaxies, determining the distribution of dark matter within these systems, and building a theoretical understanding of how these systems formed and evolved.

Page last updated: 29 September 2011 at 16:05