[Skip to Content]
The Andromeda galaxy, a beautiful example of disk galaxy. Image credits: APOD.

The Andromeda galaxy, a beautiful example of disk galaxy.
Image credits: APOD.

In our modern view of galaxy formation and evolution, the cold gas component plays a central role. Atomic hydrogen is the most abundant element and is the fuel for future star formation, thus it is a key component of galaxies. Moreover, galaxies are no longer thought of as isolated entities, but self-regulated systems whose life is governed by a balance between gas replenishment (via inflows from the intergalactic medium) and consumption (via star formation) or ejection (outflows) – the so-called gas cycle. Thus, we cannot understand galaxies without knowing about their gas reservoirs.

Our knowledge of the gas cycle and its connection to galaxy properties and their environments is still somewhat limited, due to lack of large, multi-wavelength data sets with deep cold gas observations. The next-generation radio surveys with the Square Kilometre Array (SKA) and its pathfinders will usher in a new era for extragalactic studies, allowing us to measure the gas content for millions of galaxies. In preparation for these new data sets, we are taking advantage of state-of-the-art surveys, which include the deepest observations of cold gas in galaxies currently available, to try to answer many open questions in this field, such as: what is the relation between gas content and galaxy structure? How does the formation of a stellar bulge affect the gas reservoir of a galaxy? Why star-forming systems such as our own Milky Way have not run out of fuel a long time ago? How did they get their gas? What are the most important processes regulating gas accretion and gas loss in the local Universe, and how do they depend on the properties and environment of galaxies?

Various projects are available in this research area. These are mainly observational, but we regularly collaborate with theorists to compare our results with predictions from galaxy formation models. Hence the student will acquire skills in processing and analysis of multi-wavelength data sets, querying and managing large data sets, statistical analysis, and comparison with theory.

These projects will place the student in an excellent position to exploit the next-generation radio surveys with the Australian SKA Pathfinder (ASKAP) in Western Australia and the Five-hundred-meter Aperture Spherical Telescope (FAST) in China.

The Sombrero galaxy from the Hubble Space Telescope, an example of a galaxy with a very prominent bulge component. Billions of old stars cause the diffuse glow of the extended central bulge. Image credits: APOD.

The Sombrero galaxy from the Hubble Space Telescope, an example of a galaxy with a very prominent bulge component. Billions of old stars cause the diffuse glow of the extended central bulge. Image credits: APOD.

Associated Researchers

Dr Luca Cortese

Senior Research Fellow

Read More