University College London
Galaxies in the local Universe come in a wide variety of shapes, colors and sizes, yet this diverse population is found to obey a vast and complex network of relations between their different properties. A global picture emerges, where galaxies mostly fall in one of two categories: either they are gas-rich, blue, spiral-like and actively star-forming, or else they are red, gas-poor and featureless. To understand how galaxies form and evolve such as to produce this picture, it is essential to pinpoint when, where and how the growth and evolution of galaxies is favoured.
The picture currently emerging suggests that the availability of gas is central to their ability to grow; they evolve as gas is allowed to cool and condense in specific regions of the cosmic web, allowing stars to be born. In other words, gas is the lifeblood of galaxies. In fact, we cannot hope to fully understand how galaxies evolve without a better picture of how galaxies are supplied in gas, how they process this gas into stars, and how some of the gas is then returned to the outside environment.
My research programme funded by the Royal Society is designed to provide some direct evidence for the different phases in the gas cycle. In particular, by using radio telescopes to probe how much cold gas is present in different types of galaxies, we can infer what are the key properties of galaxies that drive the accretion of new gas to fuel the star formation process, and which properties set the efficiency of the conversion of the gas into stars.
My group and I also work to define and calibrate new observational techniques in order to investigate the link between gas and star formation in extreme galaxies, in particular galaxies that have very low masses, and those in the very distant Universe. This is done by combining our large data sets with new simulation codes and modern statistical methods.
Interests and expertise (Subject groups)