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Astronomy Colloquium
"Do Supermassive Black Holes Co-Evolve with Their Host Galaxies?"
Date: Thursday, October 13th
Time: 3:30 pm
Place: 4421 Sterling Hall
Speaker: Chien Peng, Carnegie Observatories
Abstract: For almost 20 years, one of the intriguing puzzles in galaxy evolution is the strong correlations that have been observed between galaxies and their central supermassive black holes. The correlations suggested that galaxies and their central black holes somehow "knew" about each other, and that their evolution occurred in lock-steps. Theoretical models painted a beautiful picture that showed how quasar activity can both regulate the growth of the black hole and cause star formation inside galaxies to cease, thereby producing strong correlations that have been observed. The energy feedback by quasars in turn may solve a number of other puzzles in galaxy evolution. In recent years, new observations from quasars, ULIRGS, maser galaxies, and dwarf galaxies, are providing an increasingly complex picture about the relationship between black holes and galaxies. I will present recent data on the BH and galaxy relations both at high redshift and locally, evidence for a changing correlation, and controversies surrounding the observations. I will also discuss why, if black holes self-regulate galaxy growth as theories suggest, that self regulation should have happened before redshift 2, and subsequently the correlation may have to be maintained via statistical merging alone. However, I will explain how statistical merging may itself be able to explain the entire correlation, such that black holes and galaxies may actually not need to know about one another. Lastly, I will tie all the quasar data with observations of "red nugget," normal, galaxies at high redshift to illustrate which direction the needle compass points, despite there being controversies that remain about selection functions and black hole mass estimates in active galaxies.
Host: Professor Christi Tremonti
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