DescriptionActive Galaxies are the most powerful and largest objects in the universe. Their power is generated by supermassive black holes, having masses between ten million and a billion times the mass of the sun, in the nuclei of these galaxies. High-resolution radio imaging of active galactic nuclei has revealed that the rotating supermassive black holes that power active galaxies somehow accomplish the remarkable feat of channeling energy derived from their rotation and accretion disks into two jets, oppositely directed along their spin axes, along which they expel matter at very close to the speed of light. This results in a remarkable phenomenon called 'superluminal' motion in which the material appears to be traveling faster than the speed of light. In the most powerful objects these jets are millions of light years in length. The combination of the latest observations in the radio, optical, X-ray and gamma-ray bands with beautiful computer simulations is now revealing for the first time how these supermassive black holes extract the energy required to power these extraordinary jets and how they focus the jets into two very narrow oppositely directed streams of particles along the spin axis. This will be a part of our Brown Bag Lecture Series. A light lunch will be provided.
Anthony Readhead, the Robinson Professor of Astronomy at the California Institute of Technology, was born in South Africa and took his BSc and BSc (Hons) degrees at the University of the Witwatersrand in Johannesburg before going to the Cavendish Laboratory in Cambridge in 1968, where he took his PhD under Antony Hewish in Sir Martin Ryle’s radio astronomy group. He then spent five years as a Royal Society Weir Research Fellow at the Cavendish Laboratory, including fifteen months as a post-doctoral fellow at the California Institute of Technology. He returned to the California Institute of Technology in 1977 and was appointed to the professorial faculty there in 1981. He has held a number of positions at the California Institute of Technology including Director of the Owens Valley Radio Observatory (1981- 1986, 2007 – present); Executive Officer of Astronomy (1990-1992; 20121-2013) and Director of the Chajnantor Observatory in Chile (2006- 2009). His scientific interests have been focused on cosmology and active galaxies and on techniques of high-resolution astronomy and imaging. He was elected to the United States National Academy of Sciences and the American Academy of Arts and Sciences in 1995.
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