Hawking - How supermassive black holes shape our Universe: at the interface of galaxy formation, cosmology and multi-messenger astronomy

我们的银河系中心有一个超大质量黑洞（SMBH），被称为人马座a *，质量是太阳的400多万倍。SMBHs位于大多数（如果不是全部）星系的中心，从低质量矮星系到巨大星系团中的巨大椭圆星系。尽管与宿主星系相比，它们的体积较小，但SMBH和星系的特性通过共同进化密切相关。SMBHs代表了宇宙中一些最极端的物体，充当着令人难以置信的高效引擎，可以将大部分在其引力作用下的物质的剩余质能（记住爱因斯坦著名的方程E=mc^2）转化为能量，即以辐射、风和喷流的形式反馈的能量。这些过程赋予了SMBH自己的声音，使它能够跨越巨大的尺度进行交流，从黑洞事件视界到远超宿主星系。在接下来的十年甚至更长时间里，许多任务（如SKA， Athena, Euclid， JWST和LISA）将不仅提供光的宇宙观测，还将提供LISA的引力波观测，从而彻底改变SMBHs的多信使天文学。从SMBH双星到单个星系，再到代表宇宙中最大质量物体并包含数千个星系的巨大星系团，这些系统将在本地宇宙中被观测到，直到它不到当前年龄的四分之一。我们将收到比以往更多的数据，为SMBHs及其星系在宇宙时间内的共同演化提供洞见。为了帮助解释大量的新观测数据，有可靠和现实的理论模型来比较是至关重要的。形成SMBHs及其宇宙环境特性的大量复杂物理过程，以及涉及的巨大尺度范围，构成了一项艰巨的挑战。使用强大的超级计算机，我将执行最先进的模拟，结合新颖的新模型和技术，为在多个尺度和不同环境中捕获广泛的物理过程提供独特的方法。这包括对双星中的SMBHs对及其周围气体盘的小规模模拟，对单个星系、星系群和星系团的高分辨率模拟，以及捕捉宇宙代表性体积的大型宇宙盒。这些模拟将结合起来，为一系列与SMBHs相关的问题提供答案，例如：- SMBHs释放的能量如何塑造星系，群和星系团的性质？-星团的状态，比如它的湍流程度或磁场的性质，如何影响SMBHs的反馈？-我们如何使用星系团来探测宇宙的潜在属性（宇宙学）？-中小企业的反馈在哪些尺度上能产生重大影响？-中小企业是如何走到一起并合并的？- SMBH合并的多信使特征是什么？总的来说，模拟及其结果将为解释未来20年发射的许多观测任务提供重要的资源，正是通过协同工作，理论和观测的结合将增强我们对天体物理学和宇宙学的理解。

Our home galaxy, the Milky Way, plays host to a super-massive black hole (SMBH) at its centre, dubbed Sagittarius A*, with a mass more than 4 million times that of the sun. SMBHs reside in the centres of most (if not all) galaxies, from low-mass dwarf galaxies to giant ellipticals in vast galaxy clusters. Despite their small sizes compared to the galaxies that host them, SMBH and galaxy properties are intimately linked through co-evolution. SMBHs represent some of the most extreme objects in the Universe and act as incredibly efficient engines that can convert a large fraction of the rest mass energy (remember Einstein's famous equation E=mc^2) of material that falls under their gravitational spell into energy, known as feedback, in the form of radiation, winds and jets. These processes give the SMBH its voice, allowing it to communicate across a vast range of scales, from the black hole event horizon to far beyond the host galaxy. Over the coming decade and beyond, many missions (e.g. SKA, Athena, Euclid, JWST and LISA) will provide observations of the Universe not only in light but with LISA also in gravitational waves, and hence revolutionise multi-messenger astronomy of SMBHs. Systems ranging from SMBH binaries to individual galaxies, up to vast clusters that represent the most massive objects in the Universe and contain thousands of galaxies, will be observed in the local Universe and out to when it was less than a quarter of its current age. We will receive more data than ever before providing insights into the co-evolution of SMBHs and their galaxies over cosmic time. To help to interpret the plethora of new observational data, it is vital to have robust and realistic theoretical models to compare to. The vast array of complex physical processes that shape the properties of SMBHs and their cosmic environment and the huge range of scales involved presents a formidable challenge. Using powerful supercomputers, I will perform state-of-the-art simulations that combine novel new models and techniques to provide a unique method for capturing a wide range of physical processes on multiple scales and in different environments. This includes small-scale simulations of pairs of SMBHs in binaries and the gas discs that surround them, high-resolution simulations of individual galaxies, groups and clusters, and large cosmological boxes that capture a representative volume of the Universe. These simulations will combine to provide answers to a range of questions related to SMBHs, such as:- How does energy released by SMBHs shape galaxy, group and cluster properties?- How does the state of a cluster, such as how turbulent it is or the properties of its magnetic fields, impact feedback from the SMBHs?- How can we use galaxy clusters to probe the underlying properties of the Universe (Cosmology)? - On what scales can feedback from SMBHs have a significant influence?- How do SMBHs come together and merge?- What are the multi-messenger signatures of SMBH mergers?Overall, the simulations and their outputs will provide a vital resource for interpreting the many observational missions launching over the next two decades, and it is by working in tandem that the combination of theory and observation will enhance our understanding of both astrophysics and cosmology.