Research on Gravitational Waves and Compact Binaries

该奖项将支持广义相对论中紧致双星系统的动力学和引力波发射的研究。在过去的五年里，LIGO和室女座对合并的恒星质量黑洞和中子星的大量观测开启了引力波天文学的时代。这些事件揭示了新的天体物理学，包括确认重元素形成的位置，发现一类新的中等质量黑洞，并为广义相对论提供了新的测试。这些观测结果也推动了LISA空间探测器的发展，并提高了最终观测极端质量比吸气（EMRIs）引力波的前景。EMRIs涉及一个恒星质量黑洞（或中子星或白矮星）螺旋进入一个超大质量黑洞（已知几乎存在于所有大型星系的中心）。这些超大质量黑洞被密集的星团包围着，经常会将致密的恒星捕获到高度偏心的轨道上。当这些致密恒星绕轨道运行时，它们会辐射引力波，导致轨道衰减，致密物体最终被超大质量黑洞吞噬（或者在白矮星的情况下可能被潮汐破坏）。发射的引力辐射将被LISA观测到。由该奖项资助的理论工作将提供对高偏心致密合并双星预期信号的改进预测。美国在引力波天文学方面处于领先地位，这些理论活动支持未来引力波观测的扩展。EMRIs对引力波的探测将提供独特的引力强场测试，探测黑洞的本质，同时还将揭示星系密集中心区域的天体物理特性。为了实现这一目标，将开发黑洞摄动理论和引力自作用力方法的新技术，并编写相关的高级计算机代码。在偏心EMRIs的后牛顿（PN）展开中，将对黑洞微扰理论和引力自作用力进行高阶的符号数学计算。这些计算将扩展到围绕旋转（Kerr）主星的一般轨道的EMRIs。这些高PN阶摄动和自力的发现支持并加强了更广泛的努力，以推进PN理论，并为合并双星的有效一体模型提供校准。PI的小组借鉴了他们近年来专门用于Schwarzschild EMRIs的完全符号代码的经验，现在为Kerr EMRIs编写了完全符号代码。产生的引力波通量和自作用力数据将被纳入绝热和绝热后的吸气计算中，为EMRI的发展提供准确的波形。这项工作的某些部分将与以前的学生和都柏林大学学院的同事合作进行。结果和部分计算机代码将在网上公布。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award will support research on the dynamics and gravitational wave emission of compact binary systems in general relativity. The numerous observations by LIGO and Virgo of merging stellar mass black holes and neutron stars over the last five years have opened up the era of gravitational wave astronomy. These events reveal new astrophysics, including confirming the site of heavy element formation, discovering a new class of intermediate mass black holes, and providing novel tests of general relativity theory. These observations also motivate development of the LISA space-based detector and raise prospects for eventual gravitational wave observations of extreme-mass-ratio inspirals (EMRIs). EMRIs involve a stellar-mass black hole (or neutron star or white dwarf) spiraling into a supermassive black hole (which are known to exist in the center of virtually all large galaxies). Surrounded by dense star clusters, these supermassive black holes will frequently capture compact stars into highly eccentric orbits. As these compact stars orbit, they radiate gravitational waves, causing the orbit to decay and the compact object to eventually be swallowed by the supermassive black hole (or potentially tidally disrupted in the case of white dwarfs). The emitted gravitational radiation will be observable with LISA. The theoretical work funded by this award will provide improved predictions of the expected signals from highly-eccentric compact merging binaries. The US is a leader in gravitational wave astronomy and these theoretical activities support future extensions of such observations. Detection of gravitational waves from EMRIs will provide unique strong field tests of gravity and probe the nature of black holes, while also uncovering astrophysical properties of the dense central regions of galaxies.To pursue this effort, development will be made of new techniques in black hole perturbation theory and gravitational self-force methods, along with writing associated advanced computer codes. Symbolic mathematical calculations of black hole perturbation theory and the gravitational self-force will be made to high order in the post-Newtonian (PN) expansion for eccentric EMRIs. These calculations will be extended to EMRIs with general orbits about a rotating (Kerr) primary. These high PN order perturbation and self-force findings support and reinforce broader efforts to advance PN theory and provide calibrations of effective-one-body models of merging binaries. The PI's group draws upon their experience in recent years with a fully symbolic code that was specialized to Schwarzschild EMRIs to now write a fully symbolic code for Kerr EMRIs. Generated gravitational wave flux and self-force data will be incorporated in adiabatic and post-adiabatic inspiral calculations to provide accurate waveforms for much of an EMRI's evolution. Some parts of this work will be conducted in collaboration with former students and with colleagues at University College Dublin. Results and some computer codes will be made available online.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.