Research on Gravitational Waves and Compact Binaries

引力波和致密双星研究

• 批准号: 2110335
• 负责人: Charles Evans
• 金额: $ 18万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2110335&HistoricalAwards=false
• 关键词: Research; Gravitational; Waves; Compact; Binaries

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.

该奖项将支持广义相对论中紧凑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Virgo对恒星质量黑洞和中子星合并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地点，发现一类新的中等质量黑洞，并提供广义相对论的新测试。这些观测也推动了丽莎天基探测器的发展，并提高了极端质量比螺旋（EMRI）最终引力波观测的前景。 EMRI涉及恒星质量黑洞（或中子星星或白色矮星）螺旋进入超大质量黑洞（已知存在于几乎所有大型星系的中心）。 这些超大质量黑洞被密集的星星团所包围，经常会将致密恒星捕获到高度偏心的轨道上。 当这些致密的恒星绕轨道运行时，它们会辐射引力波，导致轨道衰减，致密的物体最终被超大质量黑洞吞噬（或者在白色矮星的情况下可能会被潮汐破坏）。发射的引力辐射将通过丽莎观测到。 由该奖项资助的理论工作将提供改进的预测，从高偏心紧凑合并双星的预期信号。 美国是引力波天文学的领导者，这些理论活动支持未来扩展此类观测。 从EMRI探测引力波将提供独特的强引力场测试和探测黑洞的性质，同时也揭示了星系密集中心区域的天体物理学性质，为了实现这一努力，将发展黑洞微扰理论和引力自作用力方法的新技术，沿着编写相关的高级计算机代码。 在偏心EMRI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符号数学计算。 这些计算将被扩展到EMRI与一般轨道的旋转（克尔）小学。 这些高PN阶微扰和自作用力的发现支持和加强了更广泛的努力，以推进PN理论，并提供校准的有效一体化模型合并的二进制文件。PI的团队借鉴了他们近年来在Schwarzschild EMRI专用的全符号代码方面的经验，现在为Kerr EMRI编写了一个全符号代码。 所产生的引力波通量和自作用力数据将被纳入绝热和后绝热螺旋计算，以提供准确的波形的大部分EMRI的演变。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。 该奖项反映了NSF的法定使命，并被认为是值得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的支持。

项目成果

Resonant self-force effects in extreme-mass-ratio binaries: A scalar model

极端质量比双星中的共振自力效应：标量模型

• DOI: 10.1103/physrevd.104.084011
• 发表时间: 2021
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Nasipak, Zachary;Evans, Charles R.
• 通讯作者: Evans, Charles R.

Post-Newtonian expansion of the spin-precession invariant for eccentric-orbit nonspinning extreme-mass-ratio inspirals to 9PN and e16

偏心轨道非自旋极端质量比螺旋的自旋进动不变量的后牛顿展开到 9PN 和 e16

• DOI: 10.1103/physrevd.106.044058
• 发表时间: 2022
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Munna, Christopher;Evans, Charles R.
• 通讯作者: Evans, Charles R.

High-order post-Newtonian expansion of the redshift invariant for eccentric-orbit nonspinning extreme-mass-ratio inspirals

偏心轨道非自旋极端质量比螺旋的红移不变量的高阶后牛顿展开式

• DOI: 10.1103/physrevd.106.044004
• 发表时间: 2022
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Munna, Christopher;Evans, Charles R.
• 通讯作者: Evans, Charles R.