Molecular cloud formation

Simulation of whirlpool galaxy

Galaxies and the Interstellar Medium

Both the evolution of galaxies, and the details of star formation, are controlled by the dynamics of the interstellar medium (ISM), which is the gaseous component of galaxies. Stars form where the gas becomes cold and dense, in massive clouds of gas known as giant molecular clouds. The number of stars which form in these clouds determine how fast gas in galaxies is depleted and hence their ultimate evolution. Since the formation and properties of molecular clouds are linked to large scale processes, such as spiral density waves and turbulence, it is vital to study molecular clouds in the context of an entire galaxy.

Here at Exeter, we perform state-of-the-art hydrodynamic simulations of galaxies to follow the gas in galaxies as it forms molecular clouds, stellar clusters, and then disperses. Our theoretical work is complimented by the ‘Exeter Outer Galaxy Survey’, a large scale observational program to map CO in the Galaxy at the finest resolution. To properly compare the observations and simulations, we also undertake radiative transfer calculations to produce synthetic HI and CO maps from the simulations.

Research areas

Spiral structure

Clare Dobbs performs simulations of galaxies to understand what produces spiral arms in local galaxies such as the Whirlpool Galaxy.

The Interstellar medium (ISM)

Clare Dobbs uses simulations to understand how physical processes such as supernovae explosions determine the distribution and properties of the ISM.

Molecular cloud formation

Clare Dobbs uses simulations of galaxies to test theories of how molecular clouds form, and to predict their properties.

Galactic surveys of the ISM

Chris Brunt conducts CO observations to determine the distribution, and properties of molecular gas in the Galaxy.

Current researchers


Dr Clare Dobbs, Dr Chris Brunt.

Post-doctorals and Fellows

Dr Stuart Sale.


Tom Bending.