Modelling compact objects for precision astrophysics

我们正在进入一个高精度天文学的时代，包括电磁和引力。第一代高灵敏度引力波探测器已达到设计灵敏度，并正在使用先进技术进行升级。LOFAR是在线的，在无线电定时精度方面提供了重大改进。与SKA无线电、爱因斯坦望远镜和空间引力波探测器丽莎相关的未来进展将补充目前高质量的X射线观测，并将使我们能够显着提高对宇宙的理解。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对涉及紧凑物体的一系列现象的模型。需要更高质量的理论来探测各种信号，并尽可能多地探测相关的物理学。这项研究计划建立在南安普顿广义相对论小组在黑洞、中子星星和引力波天体物理学方面的专业知识基础上，旨在加深对致密物体动力学的理解，相关的观测特征以及如何使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，广义相对论扰动理论或数值模拟）和物理输入（例如，超流性、磁场或引力辐射反应）。总的目标是开发出大大改进的模型，这些模型可以根据今后在一系列通道中进行的高精度观测进行检验，中子星是独特的天体物理实验室，其建模需要知之甚少的物理学。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结合起来，磁流体力学是对超流体和超导体的描述，可能是物质的奇异相，如解除限制的夸克-胶子等离子体，当然还有广义相对论。更好地理解中子星星动力学是这项建议的主要目标之一。我们将开展两个平行项目，重点是中子星星动力学和相关的天体物理方案。拟议的工作是直接相关的引力波物理，导致天体物理学动机的信号搜索，并提供了有用的见解相关的电磁观测问题。我们的目标是构建准确的中子星星脉动模型，可以测试对最近的观测与磁星巨星耀斑相关的振荡，这将告知未来有针对性的引力波搜索的r-模式振荡在快速旋转的中子星。我们将提供改进的模型，神秘的毛刺和其他定时现象，在无线电频率计。我们还计划考虑环境影响，例如，磁层在间歇性双星背景下的作用，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。特别是，丽莎有令人兴奋的前景来探测星系中心致密物体进入大质量黑洞的辐射螺旋。这些事件的引力波形是对大质量黑洞附近强引力的非常有效的探测，并有望在最极端的领域对引力理论进行精确的测试。为了实现这一承诺，我们需要对相对论辐射反应效应有一个很好的理论理解。最近在引力自作用力问题上的进展为这一领域的工作提供了重要的动力。在此基础上，我们将探索自作用力计算，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为二元螺旋的通用模型提供信息。

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.