Physical Society Colloquium

Interview for Faculty Position

Quasars and Cosmology:
A Quasologist's Perspective on the History of the Universe

Gordon T. Richards

Princeton University

I review our current understanding of the role of quasars in the history of the universe. The study of quasars, particularly their evolution as a function of time and luminosity (i.e., the luminosity function) has been the subject of renewed interest in recent years. This interest stems from three simple results: 1) all massive galaxies appear to host supermassive black holes, 2) there is an intimate relationship between the evolution of these supermassive black holes and their host galaxies, and 3) all quasars are likely to have winds and other types of feedback mechanisms that influence the growth of structure within dark matter halos. As such, quasars may play a larger role in the history of the Universe that we might have previously expected. I will review how recent surveys for quasars such as the Sloan Digital Sky Survey are contributing to this body of work by providing observations that are crucial for testing of theoretical models of galaxy formation and evolution.