HPC Resources for Theoretical Astrophysics at the University of Leicester

黑洞的吸积是从常规物质中提取能量的最有效方式。因此，引力能为宇宙中最明亮的物体提供动力。与此同时，引力的累积性质使它在决定所有尺度上物质的结构和进化方面起着决定性的作用。在各种宇宙背景下，对这两个方面的理论理解——吸积，以及母星系的结构和演化——是我们研究的关键主题。在最小的尺度上，包含黑洞的紧密双星系统为研究吸积过程（如盘的形成和稳定性）提供了一条非常容易处理的途径。但同样重要的是要了解这些双星本身的长期演变，以及其他星系的标准和超亮X射线种群。同样，天文学家想要了解超大质量黑洞（SMBH）的吸积如何为活动星系核（AGN）提供动力。但他们也希望知道这些天体是如何融入星系结构和形成的总体图景的。伽马射线暴（GRBs）提供了另一个例子，其中吸积过程的研究与理解宿主星系以及其中的恒星和双星演化密切相关。暗物质提供了结构形成和演化的潜在井，因此我们需要了解它的物理特性，以便有一个完整的宇宙结构形成理论。我们从理论上研究了所有这些天体，在过去的十年里，我们的重点已经强烈地转向了超大质量/超星系系统。

Accretion on to a black hole is the most efficient way of extracting energy from conventional matter. Gravitational energy thus powers the most luminous objects in the Universe. At the same time, gravity's cumulative nature gives it a decisive role in determining the structure and evolution of matter at all scales. The theoretical understanding of these twin aspects -- accretion, and the structure and evolution of the parent systems -- are the key theme of our research, in various cosmic contexts. On the smallest scale, close binary systems containing black holes offer a highly tractable route to studying accretion processes such as disc formation and stability. But it is important also to understand the long--term evolution of these binaries themselves, and the standard and ultraluminous X--ray populations of other galaxies. Similarly, astronomers want to understand how accretion on to supermassive black holes (SMBH) powers active galactic nuclei (AGN). But they also wish to know how these objects fit into the general picture of galaxy structure and formation. Gamma--ray bursts (GRBs) offer another example where the study of accretion processes is closely linked to understanding the host galaxy, and stellar and binary evolution within it. Dark matter provides the potential wells within which structures form and evolve and we therefore need to understand its physical properties in order to have a complete theory of structure formation in the Universe. We study all of these objects theoretically, and our emphasis has shifted strongly towards supermassive/extra\-galactic systems over the last decade.