The Monster at the Heart of the Milky Way Andrea Ghez University of California Los Angeles 2015 Maggie & Nick DeWolf FREE Physics Lectures Wheeler Opera House 5:30 pm Wednesday 21st January Wheeler Opera House Physics Cafe at 4:30 Through the capture and analysis of two decades of high-resolution imaging, Dr. Ghez and her team have moved the case for a supermassive black hole at the center of our galaxy from a possibility to a certainty. Dr. Ghez’ work also explores the role that black holes play in the formation and evolution of galaxies. Several unexpected surprises have been revealed including the presence of massive young stars orbiting in close proximity of a black hole and a possible gas cloud headed straight for the black hole in our galaxy. The origin of these stars and putative gas cloud are a challenge to explain, but may provide key insight into the growth of the central black hole. Andrea M. Ghez, distinguished professor of Physics & Astronomy and head of UCLAs Galactic Center Group, is a world-leading expert in observational astrophysics. She earned her B.S. in Physics from MIT in 1987 and her Ph.D. from Caltech in 1992. She has been on the faculty at UCLA since 1994. Dr. Ghez has used the Keck telescopes to demonstrate the existence of a supermassive black hole with a mass 4 million times that of our sun at the center of our galaxy. This is the best evidence yet that these exotic objects really do exist, and provides us with a wonderful opportunity to study the fundamental laws of physics in the extreme environment near a black hole. The case for a massive black hole at the center of our Galaxy has been argued over the past few decades, however it has not been previously possible to prove this tantalizing hypothesis. In principle, the stars in the vicinity of the Galactic Center could be used as “test particles” to probe for the presence of a central dark mass but the density of stars in this region is so high that previous studies have reached an impasse due to limitations in angular resolution. With the ability to carry out diffraction-limited imaging at Keck, Prof. Ghez has mapped the Galactic Center with unprecedented angular resolution. These observations reveal stars moving at apparent speeds as high as 12,000 km/sec (~4% the speed of light!) whose orbits imply the presence of a mass of dark matter 3.7 million times the mass of the Sun. This leads to the conclusion that our Galaxy harbors a massive central black hole and if one as inactive as ours support a central black hole, then one might assume that such objects can be found at the centers of all galaxies! Professor Ghez has actively disseminated her work to a wide variety of audiences through more than 100 refereed papers and 200 invited talks, as well features in textbooks, documentaries, and science exhibits. She has received numerous honors and awards including the Crafoord Prize, a MacArthur Fellowship, election to the National Academy of Sciences and the American Academy of Arts & Sciences, the Aaronson Award from the University of Arizona, the Sackler Prize from Tel Aviv University, the American Physical Societys Maria Goeppert-Mayer Award, the American Astronomical Societys Newton Lacy Pierce Prize, a Sloan Fellowship, a Packard Fellowship, and several teaching awards. Her most recent service work includes membership on the National Research Councils Board on Physics & Astronomy, the Thirty-Meter-Telescopes Science Advisory Committee, the Keck Observatory Science Steering Committee, and the Research Strategies Working Group of the UC Commission on the Future. galacticcenter.astro.ucla.edu
Posted on: Mon, 19 Jan 2015 21:36:11 +0000