Measuring the spin distribution of supermassive black holes is of critical importance for understanding how these black holes and their host galaxies form and evolve over time, yet this type of study is only in its infancy. This brief describes how astronomers measure spin in supermassive black holes using X-ray spectroscopy. It also reviews the constraints that have been placed on the spin distribution in local, bright active galaxies over the past six years, and the cosmological implications of these constraints. Finally, it summarizes the open questions that remain in this exciting new field of research and points toward future discoveries soon to be made by the next generation of space-based observatories.

Autorentext
Dr. Brenneman received her B.A. in Astrophysics in 1999 from Williams College (Williamstown, MA), and her Ph.D. in Astronomy in 2007 from the University of Maryland (College Park, MD). She held a NASA postdoctoral fellowship at the Goddard Space Flight Center (Greenbelt, MD) from 2007-2009, and is presently a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics (Cambridge, MA). She is the author of several research papers on the topic of black hole angular momentum in active galaxies, including the first published constraint on spin in a supermassive black hole (2006), and a Sky & Telescope cover story on spinning black holes (May 2011). She is currently working to measure black hole spin in a large sample of active galaxies, and to understand the role that spin plays in the growth and evolution of supermassive black holes and their host galaxies.

Inhalt
I. Introduction on importance of black hole spin.- II. Description of spectroscopic techniques used to measure spin in AGN.- III. Review of current spin measurements.- IV. Implications for the growth of black holes and their host galaxies.- V. Future Directions.