Sources for Gravitational Wave Astronomy

随着第一代高灵敏度引力波探测器以设计灵敏度工作，对于广义相对论和天体物理学来说，这是一个令人兴奋的时代。随着先进探测器的升级计划和空间探测器LISA将于2015年左右发射，我们希望很快能够利用引力波数据来了解更多关于宇宙的信息。由于引力波天文学有可能探测其他黑暗或隐藏的过程，它有望显著改变我们对黑洞和中子星的理解。收集到的信息将是对电磁观测信息的补充。然而，我们需要改进我们目前的预测来源模型。不仅需要更好的模型来探测引力波，而且还需要尽可能多的物理探测。这项研究建议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，旨在加深对黑洞和中子星如何发出引力波的理解，以及如何利用这些信号来提供有关相关物理的信息。拟议的方案具有高度相互关联的性质，有四个不同的项目需要类似的方法(例如一般相对论微扰理论或数值模拟)和物理输入(例如超流、磁场或引力辐射反应)。总体目标是从涉及致密天体的一系列天体物理场景中开发出显著改进的引力波模型。中子星是独特的天体物理实验室，其建模需要许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与磁流体力学结合起来，描述超流体和超导体，潜在的奇异物质相，如去受限的夸克-胶子等离子体，当然还有广义相对论。由于它们可以以各种方式辐射引力波，因此更好地了解中子星动力学是这项提议的关键目标之一。为了做到这一点，我们将开展三个平行项目，重点是中子星振荡、旋转动力学和完全非线性模拟，以研究中子星的诞生。这项拟议的工作不仅与引力波物理有关，还将为与电磁观测相关的问题提供有用的见解。我们的目标是建立准确的磁星脉动模型，可以根据最近观测到的与磁星巨型耀斑相关的振荡来进行测试。我们对旋转效应的研究应该有助于揭示脉冲星的毛刺，而非线性模拟将有助于更好地理解磁化恒星的形成和伽马射线暴的中心引擎。黑洞与周围环境以复杂的方式相互作用。这种相互作用的建模是一个严峻的挑战。在拟议的研究计划中，我们将考虑黑洞物理的两个重要问题。我们将使用非线性模拟来研究引力崩塌的后期阶段，黑洞的诞生，以及可能围绕它的碎片盘的动力学。我们还将研究由星系核心中的引力俘获引起的双星系统的辐射反应驱动激发的问题，这是LISA最感兴趣的来源之一。尽管这两个问题截然不同，但它们都需要对时空动力学进行精确的建模。最近在黑洞二元模拟方面的进展为这一领域的工作提供了巨大的动力，最终目的是利用引力波数据来探测黑洞附近的强弯曲时空。

With the first generation of highly sensitive gravitational wave detectors operating at design sensitivity, this is an exciting time for general relativity and astrophysics. With upgrades to advanced detectors planned and the space based detector LISA due for launch around 2015, we hope to soon be able to use gravitational wave data to learn more about the Universe. With its potential for probing otherwise dark or hidden processes, gravitational wave astronomy promises to change our understanding of, in particular, black holes and neutron stars significantly. The information gleaned will be complementary to that from electromagnetic observations. However, we need to improve our current models of the predicted sources. Better models are needed not only to detect the gravitational waves in the first place, but also to probe as much 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 how gravitational waves are emitted by black holes and neutron stars, and how the signals can be used to provide information about the involved physics. The proposed programme is of a highly interconnected nature with four different projects 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 for gravitational waves from a range of astrophysical scenarios involving compact objects. 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. Since they can radiate gravitational waves in a variety of ways, achieving a better understanding of neutron star dynamics is one of the key aims of this proposal. To do this we will carry out three parallel projects, focused on neutron star oscillations, rotational dynamics and fully nonlinear simulations to study neutron star birth. The proposed work is not only relevant for gravitational wave physics, it will also provide useful insights into problems relevant for electromagnetic observations. We aim to contruct accurate models of magnetic star pulsations that can be tested against recent observations of oscillations associated with magnetar giant flares. Our studies of rotational effects should shed light on the pulsar glitches, while the nonlinear simulations will lead to a better understanding of the formation of magnetised stars and the gamma-ray burst central engine. Black holes interact with their environment in complex ways. The modelling of this interaction provides a serious challenge. In the proposed research programme we will consider two important problems for black hole physics. We will use nonlinear simulations to study the late stages of gravitational collapse, the birth of a black hole and the dynamics of the debris disk that may surround it. We will also study the problem of radiation reaction driven inspiral of a binary system resulting from gravitational capture in a galaxy core, one of the most interesting sources for LISA. Although these two problems are rather different, they both require accurate modelling of spacetime dynamics. Recent progress on black hole binary simulations provides significant momentum for work in this area, which is ultimately aimed at using gravitational wave data to probe the strongly curved spacetime near a black hole.