General Relativistic Astrophysics

在过去的一年里，引力和相对论天体物理学取得了一系列杰出的成就。来自合并黑洞的引力波的突破性探测清楚地展示了这一天文学新领域的发现潜力。随着引力波仪器灵敏度的提高，以及更广泛的探测器网络上线，预计将探测到更广泛的震源。对双中子星螺旋和合并后期阶段的观测尤其令人兴奋，特别是因为这种事件可能有对应的电磁发射(例如短伽马射线暴)。随着我们认真地进入引力波天文学时代，有很多理由让我们充满热情。LISA探路者展示了天基仪器所需的无阻力干涉测量的技术准备，随后欧空局选择了LISA项目(定于本世纪30年代发射)，确保了引力物理学将在(至少)未来20年继续发展。引力波天文学的主要重点是涉及中子星和黑洞的问题。这些令人着迷的神秘物体涉及真正鼓舞人心的科学，代表着探索物理学极端的独特实验室。黑洞天体物理影响一系列基本问题，从引力的性质到宇宙学中的问题，例如与早期宇宙的结构形成有关的问题。与此同时，中子星观测使我们能够探测极端条件下物质的状态，为我们提供了补充从欧洲核子研究中心的大型强子对撞机等对撞机收集到的信息。这些高度相对论的系统的模型涉及广泛的物理范围，这在实验室里是无法获得的。随着我们观测能力的提高，我们已经到了需要精确建模来解释数据和促进观测的地步。拟议的研究代表了一项连贯的计划，旨在探索黑洞和中子星的天体物理学，以提高我们对宇宙基本物理定律的理解，并揭示自然如何在我们目前的理解被打破的尺度上运行，这仍然是STFC任务的核心主题。中子星建模涉及非常复杂的物理学，涉及一系列天体物理现象，主要通过无线电计时和X射线计时和光谱来探索。中子星还可能辐射出可探测到的引力波(通过各种场景，从它们诞生的超新星核心坍塌到双星系统的合并)。挑战在于对观测到的信号进行解码，以“约束”当前的理论，包括难以捉摸的超核物质状态方程。这项提议旨在提高我们对中子星的理解，包括它们的演化和动力学，以及它们如何与环境相互作用。黑洞以一种复杂的方式与环境相互作用。这种相互作用的建模是一个严峻的挑战。特别是，我们需要对引力辐射驱动的反应驱动的双星系统的激发和最终结合的精确描述。这个问题是正在进行和未来的引力波搜索的核心问题。星系核中的大质量黑洞对致密物体的引力捕获对于LISA这样的太空仪器尤其相关，因为信号编码的信息可以实现高精度的广义相对论测试和大质量黑洞物理的精确研究。拟议研究的一个中心目标是对目前的地面和未来的天基观测站可探测到的双源中的螺旋动力学进行建模。

The last year has seen a string of outstanding successes in gravity and relativistic astrophysics. The breakthrough detection of gravitational waves from merging black holes provided a clear demonstration of the discovery potential of this new area of astronomy. As the sensitivity of gravitational-wave instruments improves, and a wider network of detectors come online, a broader range of sources is expected to be detected. Observations of the late stages of binary neutron star inspiral and merger are anticipated with particular excitement, especially since such events may have counterpart electromagnetic emission (e.g. short gamma-ray bursts). As we enter the era of gravitational-wave astronomy in earnest, there are many reasons for enthusiasm. The LISA Pathfinder demonstration of technology readiness of the drag-free interferometry required for space-based instruments, followed by the ESA selection of the LISA project (due for launch in the 2030s), ensures that gravitational physics will continue to develop for (at least) the next two decades.The main emphasis of gravitational-wave astronomy is on problems involving neutron stars and black holes. These fascinating and enigmatic objects involve truly inspirational science and represent unique laboratories for the exploration of the extremes of physics. Black-hole astrophysics impacts on a range of fundamental issues, from the nature of gravity to problems in cosmology, e.g., associated with structure formation in the early Universe. Meanwhile, neutron star observations allow us to probe the state of matter under extreme conditions, providing us with information which complements that gleaned from colliders like the LHC at CERN. The modelling of these highly relativistic systems involves a broad range of physics that is not accessible in the laboratory. As our observational capabilities improve, we are reaching the point where precise modelling is required both to interpret data and to facilitate the observations in the first place. The proposed research represents a coherent programme aimed at exploring the astrophysics of black holes and neutron stars in order to improve our understanding of the fundamental laws of physics of the Universe and reveal how nature operates on scales where our current understanding breaks down, a theme that remains central to the STFC mission.Neutron star modelling involves much complex physics and relates to a range of astrophysical phenomena, primarily probed by radio timing and X-ray timing and spectra. Neutron stars may also radiate detectable gravitational waves (through a variety of scenarios ranging from the supernova core-collapse in which they are born to the merger of binary systems). The challenge is to decode observed signals to "constrain" current theories, including the elusive equation of state for supranuclear matter. This proposal aims to improve our understanding of neutron stars, including their evolution and dynamics and how they interact with their environment.Black holes interact with their environment in a complex fashion. The modelling of this interaction provides a serious challenge. In particular, we need a precise description of the gravitational radiation-reaction-driven inspiral and eventual coalescence of binary systems. This problem is central for ongoing and future gravitational-wave searches. The gravitational capture of compact objects by massive black holes in galactic nuclei is particularly relevant for space-borne instruments like LISA, as the signal encodes information that allows high-precision tests of general relativity and precision studies of massive black-hole physics. A central objective for the proposed research is to model the inspiral dynamics in binary sources detectable by current ground-based and future space-based observatories.