The Molecular Astrophysics of Stars and Galaxies

Anywhere in the Universe, gas that is sufficiently dense will form a range of molecules. Emissions from these molecules - often in the radio régime - excited by collisions can be detected in many locations in our Galaxy and in external galaxies, including some of the most distant objects in the Universe. Astronomers use the information contained in the detected radiation to infer the conditions in the emitting region, and so are able to investigate the processesoccurring in, for example, star forming regions, circumstellar matter, active galactic nuclei, and the early Universe.