The group environment: a key to galaxy evolution and quasar activity

附近最大的星系在宇宙只有现在年龄的四分之一到一半的时候，就形成了它们的大部分恒星和它们中央的超大质量黑洞。 这些过程发生的时间和黑洞与其宿主星系质量之间明显固定的关系，都指向这两种现象之间的联系。 我提出的研究计划解决了黑洞生长和星系演化的一个有趣的交叉点，重点是物理过程和星系群环境，如下面列出的三个项目所述。 (1)确定类星体宿主星系发生了什么：在一个星系中，气体的运动直接影响着燃料供应过程，该星系中的黑洞作为类星体活跃地生长。 换句话说，类星体是由两个富含气体的星系戏剧性的合并引发的，还是更微妙的星系相互作用导致了气体流入星系核？ (2)了解类星体反馈：对类星体尘埃风的计算机模拟提供了测量外流结构和速度的可能性。 有了这两个重要的参数，风的动能--以及它们影响星系宿主的潜力--就可以确定了。 (3)致密星系群中的星系核和恒星群的特征：局部宇宙中的致密星系群显示出从活跃的星星形成到静止的快速演化的证据，因为即使是微妙的星系相互作用的影响也会通过触发星星形成来增强气体的处理。 找到恒星的年龄并窥视星系中心将开启对这些系统中恒星聚集的研究。 这三个项目结合起来形成了一个连贯的计划，用于研究超大质量黑洞作为发光类星体的生长与大质量星系中恒星的形成之间的关系，这是在群体环境中培育的过程。

The most massive nearby galaxies built up the bulk of their stars and their central supermassive black holes at a time when the Universe was a quarter to a half its current age. The coeval timing of these processes and the apparently fixed relationship between the masses of black holes and their host galaxies point towards a connection between these two phenomena. My proposed research program addresses an intriguing intersection of black hole growth and galaxy evolution by focusing on the physical processes and the galaxy group environment that link them as outlined in the three projects listed below. (1) Determining What Happens to a Quasar Host Galaxy: The motions of gas within a galaxy hosting a black hole actively growing as a quasar directly bear on the fueling process. In other words, was the quasar triggered by a dramatic merger of two gas-rich galaxies or were more subtle galaxy interactions the cause of the inflow of gas to the nucleus? (2) Understanding Quasar Feedback: Computer simulations of the dusty winds from quasars offer the potential to measure the structure and velocity of the outflows. With these two important parameters, the kinetic energy of the winds - and therefore their potential to affect their galaxy hosts - can be determined. (3) Characterizing Nuclei and Stellar Populations in Compact Group Galaxies: Compact group galaxies in the local Universe show evidence for rapid evolution from actively star forming to quiescent as the effects of even subtle galaxy interactions enhance the processing of gas through triggered star formation. Finding the ages of the stars and peering into the galaxy centres will open up the study of stellar buildup in these systems. These three projects combined form a coherent program for investigating the relationship between the growth of supermassive black holes as luminous quasars and the build-up of stars in massive galaxies, processes fostered in the group environment.