Lecture 30: Active Galaxies & Quasars
What are Active Galaxies and Quasars? We have good reason to \nthink that buried deep in the hearts of nearly every (?) bright galaxy is \na supermassive black hole with masses of millions or even billions of\ntimes the mass of the Sun. Most, like the one in our Milky Way, \nare quiescent, but in about 1% of galaxies, they are fed enough matter\n(up to about a sun's worth per year), and light up as an Active Galactic\nNucleus (AGN) that can outshine an entire galaxy full of billions of stars.\nThis lecture reviews the observed properties of Active Galaxies, the\nriddle of the Quasars, and the recognition that they are powered by\nthe accretion of matter onto supermassive black holes. The lecture ends\nwith some open questions in this active area of current research.\nRecorded 2006 February 16 in 1008 Evans Laboratory on the Columbus campus\nof The Ohio State University.