报告人：美国普林斯顿大学Jeremiah Ostriker教授

题 目： AGN Feedback

时 间： 2009年9月7日 (星期一) 上午 9：00-11：00
地 点： 中科院上海天文台 天文大厦3楼大会议室

语 言： 英语

联系人：中国科学院上海天文台 科技处周凌瑜

　　　  021-64386191-813，13564322651

　　　  中国科学院上海天文台 星系宇宙学中心 研究员 袁峰

　　　  021-64386191-261

报告人简介：

Jeremiah Ostriker，美国普林斯顿大学教授、校监，世界著名理论天体物理学家，在天体物理的许多领域都做出了杰出贡献, 获得了世界各国的很多奖项和荣誉，包括美国科学界最高奖项——美国国家科学勋章。

报告摘要：

Black holes in the centers of galaxies will be fed by accretion of ambient gas whenever gas reaches those central regions. This can be due to mergers, but even without mergers the evolution of the stellar populations of normal galaxies provides very large amounts of gas. Much of that gas will cool and fall to the centers of the systems, where it will induce starbursts and accretion events. We follow these events with a high resolution hydrodynamic code, allowing for radiative transfer, supernovae and other relevant physical processes. We find that the high energy output from these objects will strongly inhibit inflow, causing episodic accretion and a low “duty cycle”. The simulations help us to understand many phenomena including the black hole stellar mass relation, the paucity of gas in ellipticals, the incidence of the “K+A” phenomena and the observed fact that most of the black holes found in galactic centers are in the “off” state. In clusters of galaxies this feedback helps to reduce and  regulate “cooling flows”.