Modelling compact objects for precision astrophysics

我们正在进入一个高精度天文学的时代，包括电磁天文学和引力天文学。第一代高灵敏度引力波探测器已经达到设计灵敏度，并正在使用先进技术进行升级。LOFAR是在线的，显著提高了无线电定时精度。未来与射电SKA、爱因斯坦望远镜和空间引力波探测器LISA相关的进展将补充当前高质量的x射线观测，并将使我们大大提高对宇宙的理解。为了最大限度地从这些进步中受益，我们需要改进我们目前的一系列涉及致密物体的现象模型。我们需要更高质量的理论来探测各种各样的信号，并尽可能多地探测相关的物理现象。这项研究计划建立在南安普顿广义相对论小组在黑洞、中子星和引力波天体物理学方面的专业知识的基础上，旨在深入了解致密物体的动力学、相关的观测特征以及如何利用信号来探测潜在的物理学。该方案具有高度相互关联的性质，有三个不同的主题，需要类似的方法（例如，广义相对论摄动理论或数值模拟）和物理输入（例如，超流动性、磁场或引力辐射反应）。总体目标是开发出显著改进的模型，这些模型可以在未来一系列渠道的高精度观测中进行测试。中子星是独特的天体物理实验室，其建模需要很多鲜为人知的物理学。为了研究它们的性质，人们必须将超核物理学与磁流体力学、对超流体和超导体的描述、物质的潜在奇异相（如定义的夸克-胶子等离子体），当然还有广义相对论结合起来。更好地理解中子星动力学是这项提议的关键目标之一。我们将开展两个并行项目，重点研究中子星动力学和相关天体物理场景。提出的工作与引力波物理学直接相关，导致天体物理学驱动的信号搜索，并为与电磁观测相关的问题提供有用的见解。我们的目标是建立精确的中子星脉动模型，可以与最近观测到的与磁星巨斑相关的振荡进行测试，并将为未来针对快速旋转中子星r模振荡的引力波搜索提供信息。我们将提供在射电脉冲星中看到的神秘故障和其他定时现象的改进模型。我们还计划考虑环境影响，例如，磁层在间歇性脉冲星背景下的作用，以及与x射线定时观测相关的吸积系统中可变扭矩的影响。激发双星本质上是宇宙中最强的引力波源。尤其值得注意的是，LISA在探测致密物体进入银河系中心大质量黑洞的辐射激励方面有着令人兴奋的前景。来自这些事件的引力波是对大质量黑洞附近强引力的极其有效的探测，并有望在其最极端的领域对引力理论进行精确的测试。为了实现这一前景，我们需要对相对论性辐射-反应效应有一个很好的理论认识。引力自作用力问题的最新进展为这一领域的工作提供了重要的动力。在此基础上，我们将探索自力计算、数值相对论和后牛顿理论之间有希望的协同作用，以便在整个质量比范围内建立双吸气的通用模型。

We are entering an era of high-precision astronomy, both electromagnetic and gravitational. The first generation of highly sensitive gravitational-wave detectors have reached design sensitivity and are being upgraded using advanced technology. LOFAR is on-line, providing significant improvements in radio timing precision. Future advances associated with the SKA in radio, the Einstein Telescope and the space based detector LISA for gravitational waves will complement current quality X-ray observations, and will allow us to improve our understanding of the Universe significantly. To benefit maximally from these advances, we need to improve our current models of a range of phenomena involving compact objects. Better quality theory is needed both to detect the various signals and to probe as much of the relevant physics as possible.This research proposal builds on the Southampton General Relativity Group's expertise in black hole, neutron star and gravitational wave astrophysics, and is aimed at developing a deeper understanding of the dynamics of compact objects, the associated observational signatures and how signals can be used to probe the underlying physics. The programme is of a highly interconnected nature with three different themes requiring similar methodology (e.g., general relativistic perturbation theory or numerical simulations) and physics input (e.g., superfluidity, magnetic fields or gravitational radiation reaction). The overall aim is to develop significantly improved models that can be tested against future high-precision observations in a range of channels.Neutron stars are unique astrophysical laboratories, the modelling of which requires much poorly known physics. In order to investigate their properties, one must combine supranuclear physics with magnetohydrodynamics, a description of superfluids and superconductors, potentially exotic phases of matter like a deconfined quark-gluon plasma and, of course, general relativity. Achieving a better understanding of neutron star dynamics is one of the key aims of this proposal. We will carry out two parallel projects, focused on neutron star dynamics and relevant astrophysical scenarios. The proposed work is of immediate relevance for gravitational-wave physics, leading to astrophysically motivated signal searches, and provides useful insights into problems relevant for electromagnetic observations. We aim to construct accurate models of neutron star pulsations that can be tested against recent observations of oscillations associated with magnetar giant flares, and which will inform future targeted gravitational-wave searches for r-mode oscillations in fast spinning neutron stars. We will provide improved models of the enigmatic glitches and other timing phenomena seen in radio pulsars. We also plan to account for environmental effects, e.g., the role of the magnetosphere in the context of intermittent pulsars and effects due to variable torques in accreting systems relevant for X-ray timing observations.Inspiralling binaries are intrinsically the strongest sources of gravitational waves in the Universe. In particular, there are exciting prospects for LISA to detect the radiative inspiral of compact objects into massive black holes in galactic centres. Gravitational waveforms from such events are extremely efficient probes of the strong gravity near the massive black hole, and promise to allow accurate tests of gravitational theory in its most extreme domain. In order to realise this promise we need a good theoretical understanding of relativistic radiation-reaction effects. Recent progress on the problem of the gravitational self-force provides significant momentum for work in this area. Building on this, we will explore the promising synergy between self-force calculations, numerical relativity and post-Newtonian theory, in order to inform a universal model of binary inspirals across the entire range of mass ratios.