The Growth of Supermassive Black Holes

Our Accretion History of AGN (AHA) project uses a wedding-cake combination of X-ray+infrared+optical surveys to assess supermassive black hole accretion over cosmic time. X-ray selection means the AGN samples are largely unbiased against obscuration, so our population synthesis model (Ananna et al. 2019)—the only model that fits all available data—fully describes 12 billion years of accretion. Infrared and optical data allow us to disentangle radiation from stars and from accretion, as well as to study the host galaxies—for which we have developed new machine-learning tools. Finally, for samples with high completeness in black hole mass, we are able to derive the Eddington Ratio distribution function, which gives insight into AGN geometry (i.e., AGN unification) and temporal evolution.

Biography: Meg Urry is the Israel Munson Professor of Physics and Astronomy, and Director of the Yale Center for Astronomy and Astrophysics; she previously served as Chair of the Physics Department at Yale from 2007 to 2013 and in the Presidential line of the American Astronomical Society 2013-2017. Professor Urry received her Ph.D. from the Johns Hopkins University and her B.S. in Physics and Mathematics from Tufts University. Her scientific research focuses on active galaxies, which host accreting supermassive black holes in their centers. She has published over 330 refereed research articles on supermassive black holes and galaxies, including one of the most highly cited review papers in astronomy. Her group uses telescopes in space and on the ground, to conduct multi-wavelength surveys, measure line widths from which black hole masses can be derived, and analyze the dominant radiation components. To interpret these data, Urry and her collaborators develop models for the evolution of black hole growth over cosmic time. In recent years, the group has developed machine learning techniques to study galaxy properties and to characterize spectral energy distributions. Some of this work is done with collaborators around the world. (Credit: https://physics.yale.edu/people/meg-urry)