Physics & Engineering Physics Colloquium

Megan Urry, Ph.D., the Israel Munson Professor of Physics and Astronomy and director of the Yale Center for Astronomy and Astrophysics, will present, “Black Holes, Galaxies, and the Evolution of the Universe.”

Black holes form at the centers of galaxies in the young Universe and, over the next 13 billion years, they grow together by factors of a million or more in mass. This growth generates energy that can affect galaxy evolution, including that of the Milky Way galaxy in which we live. In this talk, Urry will describe how recent “wedding cake” X-ray+infrared+optical surveys of the sky have led to a quantitative description of black hole growth over the last ~12 billion years. Most Active Galactic Nuclei (AGN) are heavily obscured and thus look like inactive galaxies in optical surveys, so our census effectively quadruples the amount of accretion, and thus the amount of energy deposited in AGN host galaxies. However, contrary to leading models, our data suggest that for only a minority of galaxies does merger-triggered AGN “feedback” cause rapid quenching of star formation.