Simulating Star Formation on a Galactic Scale

Spiral galaxies are continuously evolving, forming stars, experiencing supernovae and interacting with other galaxies. In the past, it has been difficult to link the large-scale dynamics of galaxies with the small-scale processes of star formation. However, with increased computing power, and by performing simulations covering different ranges of scales, it is starting to become possible to study star formation in a galactic context. Although spiral galaxies are full of diffuse gas, stars arise specifically in regions where the gas is relatively cold and dense. Typically that dense gas is located in clouds, the most massive of which are called giant molecular clouds because they contain molecules, whereas other parts of the interstellar medium are mostly ionized gas. Giant molecular clouds contain young stars and ongoing star formation, and thus are often bright and colorful. Giant molecular clouds are the defining piece in the whole process of star formation in galaxies.