Fiona A. Harrison, Benjamin M. Rosen Professor of Physics and Astronomy, Caltech
Much of what we know observationally about black holes comes from studying how they affect their immediate environment. The X-ray band is a particularly powerful tool for understanding both stellar remnant black holes as well as supermassive black holes, because it can probe the regions within a few gravitational radii of the singularity. I will discuss how the Nuclear Spectroscopic Telescope Array (NuSTAR) high energy X-ray mission is providing the most sensitive observations to-date of black holes in our Galaxy and beyond in this region of the electromagnetic spectrum. These observations can constrain the properties of black holes, of the energetic phenomena in their immediate surrounds, and probe powerful outflowing winds that can affect the large scale properties of galaxies.