Compact Objects

Stellar mass black holes and neutron stars litter the Milky Way galaxy are the compact remnants of massive star evolution. Some of these so-called compact objects find themselves in orbit with other, regular stars, from which they can siphon off matter. This "growth through cannibalization" process is called accretion and it turns an otherwise stealthy black hole into one of the brightest objects in the universe since the big bang, most of it coming it at X-ray energies. These object are thus aptly named X-ray binaries.

Professor Heinz's group studies how these "small" black holes grow and how their growth (a) affects their environment and (b) how we can use observations of X-ray binaries to study matter under the most extreme conditions and hopefully learn more about the nature of spacetime itself around these most extreme of objects.

On much large scales, black holes are also found in the center of every massive galaxy. Compared to the black holes in X-ray binaries, they weigh in at about a million to a billion times more than stellar mass black holes. Nonetheless, they act in ways very similar to stellar mass black holes. Professor Heinz's group is studying the large scale impact of these objects on the galaxies they live in, and beyond.

Recent studies show that these supermassive black holes can affect cosmic structure on scales that are a hundred times bigger than a typical galaxy by releasing tightly bundled streams of relativistic plasma called jets.

Using numerical simulations, they are studying the impact of black holes on their environments and the role growing blackholes play in the growth of cosmic structure. These models are complemented by a program of X-ray observations of compact objects of all scales, from X-ray binaries to supermassive black holes in galaxy clusters.