General Relativistic Astrophysics

过去的一年里，在引力和相对论天体物理学方面取得了一系列杰出的成就。对黑洞合并产生的引力波的突破性探测清楚地证明了天文学这一新领域的发现潜力。随着引力波仪器灵敏度的提高，以及更广泛的探测器网络的上线，预计将探测到更广泛的源。预计将对双中子星星螺旋和合并的后期阶段进行观测，特别是因为这种事件可能有对应的电磁发射（例如短伽马射线爆发）。当我们认真地进入引力波天文学时代时，有很多理由对此充满热情。丽莎探路者演示了天基仪器所需的无阻力干涉测量技术的成熟性，随后欧空局选择了丽莎项目（定于21世纪30年代发射），确保引力物理学将（至少）在未来20年内继续发展，引力波天文学的主要重点是涉及中子星和黑洞的问题。这些迷人而神秘的物体涉及真正鼓舞人心的科学，并代表了探索物理学极端的独特实验室。黑洞天体物理学对一系列基本问题产生影响，从引力的性质到宇宙学问题，例如，与早期宇宙的结构形成有关与此同时，中子星星观测使我们能够探测极端条件下的物质状态，为我们提供的信息补充了从欧洲核子研究中心（CERN）的大型强子对撞机（LHC）等对撞机收集的信息。这些高度相对论性系统的建模涉及实验室无法获得的广泛物理学。随着我们观测能力的提高，我们正在达到这样一个地步，即首先需要精确的建模来解释数据并促进观测。拟议的研究是一个连贯的方案，旨在探索黑洞和中子星的天体物理学，以提高我们对宇宙物理学基本定律的理解，并揭示自然如何在我们目前的理解崩溃的尺度上运作，这一主题仍然是STFC使命的核心。中子星星建模涉及非常复杂的物理学，并与一系列天体物理现象有关，主要通过无线电定时和X射线定时和光谱来探测。中子星也可能辐射出可探测到的引力波（通过各种各样的场景，从它们诞生的超新星核心坍缩到双星系统的合并）。挑战在于解码观测到的信号，以“约束”当前的理论，包括难以捉摸的超核物质状态方程。该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，我们需要一个精确的描述引力辐射反应驱动的螺旋和最终合并的双系统。这个问题是正在进行的和未来的引力波搜索的核心。星系核中的大质量黑洞对致密物体的引力捕获与丽莎等星载仪器特别相关，因为信号编码的信息允许对广义相对论进行高精度测试和对大质量黑洞物理学进行精确研究。拟议的研究的一个中心目标是建立模型的螺旋动力学在目前的地面和未来的天基天文台可检测的二进制源。

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.