High energy astrophysics studies the universe at its most extreme. Its focus is the understanding of compact objects and the processes occurring in their vicinity when they grow through accretion, the properties of ionizing cosmic radiation, and the acceleration and propagation of relativistic and non-thermal particle distributions. Theoretical high energy astrophysics uses special and general relativity and fluid mechanics, and high-energy particle physics to describe objects and astrophysical systems. Observing these systems requires orbiting X-ray and gamma ray telescopes to observe the primary radiative signatures of high-energy phenomena, as well as broad band observations from radio to the TeV to study their broad non-thermal energy distributions.
Building on a long tradition of studying the high energy universe, both the Astronomy and the Physics Departments at the UW-Madison are pursuing vibrant research programs in high energy astrophysics.
High energy astrophysics research in the Astronomy department includes programs in theoretical modeling of relativistic jets and black hole atmospheres, numerical simulations AGN feedback, broad band observations of AGN, X-ray binaries, novae, and cataclysmic variables. In addition, the physics department is active in the development of X-ray instrumentation and is the PI institution for the TeV neutrino telescope Ice Cube, as well as other high energy particle observatories.