My research interests lie in the X-ray astrophysics of nearby galaxies. Galaxies are gravitationally-bound systems of many billions of stars, sat alongside interstellar gas and dust and a mysterious "dark matter" component. However, in X-rays their emission is generally dominated by a small number of individual objects with exotic properties - usually black holes or neutron stars, illuminated in X-rays by matter falling into their deep gravitational potential wells - and a hot interstellar gas component energised by supernova explosions. As a simple illustration of this contrast, the picture to the right shows images of the Southern Pinwheel Galaxy (M83) in both the optical and X-ray regimes.
As a result of this unique view, the study of X-ray emission from galaxies is of great importance to many fields, addressing issues such as the life-cycle of matter, the end points of stellar evolution and the physics of extreme environments. An understanding of the high energy phenomena revealed by X-ray studies can therefore add crucial elements to our picture of the Universe, and its evolution over cosmic time.