Biography: Professor Begelman is a Distinguished Professor in the Department of Astrophysical and Planetary Sciences. He has made highly influential contributions to high-energy theoretical astrophysics. His ground-breaking papers on the origins of extragalactic radio sources, “quasi-stars,” and the astrophysics of black holes have made seminal contributions to our understanding of and evidence for black holes in the Universe. He is one of the world’s pre-eminent scholars on the evidence for and astrophysical phenomena related to black holes, including active galactic nuclei, extragalactic radio sources, and accretion disks. (From University of Colorado Boulder).