Modelling Accretion Disk Winds

所有类星体都由同一个中心引擎提供动力：一个被发光吸积盘包围并提供能量的超大质量黑洞。在所有类星体中，大约有15%的类星体显示出明显的证据，表明从这些圆盘中产生了强大的外流，其形式是宽阔的蓝移吸收线。然而，这些所谓的“宽吸收线类星体”（balqso）只是冰山一角：由于圆盘驱动的风不可能是球形的，balqso只是在一个特别有利的方向上观察的类星体的子集。实际上，“所有”类星体都可能驱动这样的风。这很重要，因为这些外流提供了一个关键的反馈机制：它们可以从类星体中带走大量的质量、能量和角动量，并将其注入周围（星系间）介质中。然而，尽管它们很重要，我们对这些吸积盘风几乎一无所知。例如，几何，运动学，甚至负责发射它们的基本驱动机构基本上仍然是未知的。这个博士项目的目的是通过模拟类星体光谱中风形成的特征来纠正这种情况。这项工作将在一个已建立的合作背景下进行（其中包括南安普顿的另外两名博士生和一名博士后），并将使用现有的最先进的蒙特卡洛辐射传输代码。我们追求的最终目标是确定类星体吸积盘风的基本参数，从而阐明它们如何调节超大质量黑洞的燃料，以及如何将能量反馈到它们的环境中。此外，我们的目标是阐明类星体的统一：我们与类星体（甚至是非bal）相关的*大多数*观测特征是否可能实际上是由盘状风形成的？

All quasars are powered by the same central engine: a supermassive black hole that is surrounded and fed by a luminous accretion disk. Approximately 15% of all quasars exhibit clear evidence for powerful outflows driven from these disks, in the form of broad, blue-shifted absorption lines. However, these so-called "broad absorption line quasars" (BALQSOs) are just the tip of the iceberg: since disk-driven winds cannot be spherical, BALQSOs are just the sub-set of quasars viewed at a particularly favourable orientation. In reality, *all* quasars are likely to drive such winds. This is important, because these outflows provide a key feedback mechanism: they can remove significant amounts of mass, energy and angular momentum from the quasar and inject it into the surrounding (inter-)galactic medium. However, despite their importance, we know almost nothing about these accretion disk winds. For example, the geometry, kinematics, and even the basic driving mechanism responsible for launching them are still basically unknown.The aim of this PhD project will be to remedy this situation by modelling the wind-formed features in the spectra of quasars. This work will be carried out in the context of an established collaboration (which includes two other PhD students and one postdoctoral fellow at Southampton) and will use an existing, state-of-the-art Monte Carlo radiative transfer code. The ultimate goal we are pursuing is to determine the fundamental parameters of quasar accretion disk winds and thus shed light on how they regulate the fueling of supermassive black holes and the feedback of energy into their environment. In addition, we aim to shed light on quasar unification: is it possible that *most* observational signatures we associate with (even non-BAL) quasars are actually shaped by disk winds?