Gravitational Radiation and Relativistic Astrophysics

激光干涉引力波天文台（LIGO）将开展理论和计算研究：(1)与实验密切相关的研究，例如热噪声、光散射噪声和光机械不稳定性的分析和方法。(2)开发了用于模拟引力波源的数值相对论工具，特别是基于伪谱方法的计算机代码，鲁棒性好、精度高、效率高。(3)利用该代码和其他理论方法深入了解引力波源，特别是预测其发射波形。待研究的源包括(a)中子星和小黑洞向中等质量黑洞的慢吸进（“极端质量比吸进”或EMRIs）， (b)黑洞双星的后期吸进，包括自旋-轨道和自旋-自旋相互作用以及可能的自旋翻转，(c)黑洞双星从吸进到坠入的转变，(d)黑洞双星的合并，以及(d)旋转中子星。(4)利用在本工作中开发的关于源的见解来构建更好的模板族以搜索波浪，并改进提取波浪所携带信息的技术。(5)参与LIGO科学合作组织的引力波搜索，使用这些模板和技术以及其他技术。这项研究旨在帮助LIGO取得成功，通过(i)增加其从各种各样的来源探测引力波的前景，以及（ii）提高其从观测到的波中提取引力波应该携带的丰富信息的能力。它还将促进高精度测量技术的进步，有助于我们对天体物理系统的理解，并有助于发展能够对高度动态时空进行稳健和精确模拟的数值方法和计算机代码。这项研究将在很大程度上由大约10名研究生和6名博士后进行。这个项目的研究类型和研究工具的多样性将为这些学生提供丰富的训练场地。

Theoretical and computational research will be carried out in support of LIGO, the Laser Interferometer Gravitational Wave Observatory: (1) Research close to experiment, e.g. analysis of and methods to reduce thermal noise, light scattering noise, and opto- mechanical instabilities. (2) Development of numerical-relativity tools for simulating gravitational-wave sources, especially acomputer code based on pseudo-spectral methods that is robust, highly accurate, and very efficient. (3) Use of this code and other theoretical methods to develop insights into gravitational wave sources, and especially predict their emitted waveforms. Among the sources to be studied are (a) the slow inspiral of neutron stars and small black holes into intermedicate-mass black holes ("Extreme mass ratio inspirals" or EMRIs), (b) the late inspiral of black-hole binaries including spin-orbit and spin-spin interactions and possible spin flips, (c) the transition from inspiral to plunge in black-hole binaries, (d) the merger of black-hole binaries, and (d) rotating neutron stars. (4) Use of the insights about sources developed in this work to construct better template families for searching for the waves, and improved techniques for extracting information carried by the waves. (5) Participation in the LIGO Scientific Collaboration's gravitational wave searches, using these templates and techniques as well as others.This research is designed to help make LIGO a success by (i) increasing its prospects of detecting gravitational waves from a wide variety of sources, and (ii) improving its ability to extract fromobserved waves the rich information that the waves should carry. It will also contribute to the advance of technology and techniques for high-precision measurement, contribute to our understanding of astrophysical systems, and contribute to the development of numerical methods and computer codes capable of carrying out robust and accurate simulations of highly dynamical spacetimes. This research will be carried out in large measure by about ten graduate students and six postdoctoral students. This program's diversity of types of research and research tools will provide a rich training ground for these students.