Research on Gravitational Waves and Black Hole Binaries

天文观测表明，几乎所有的大质量星系都有一个位于其中心的超大质量黑洞。这些黑洞被密集的星团包围，经常会将恒星捕获到高度偏心的轨道上。这些恒星中的一小部分将是致密天体：恒星质量的黑洞或中子星。当这些致密恒星围绕轨道运行时，它们会发出引力波，导致轨道衰变，恒星最终会被超大质量黑洞吞噬。发射的辐射有可能在未来的空间引力波探测器中被观测到。由该奖项资助的理论工作将提供对高度偏心的紧凑合并双星的预期信号的更好理解。探测到这种极端质量比双星的引力波将提供一种独特的引力强场测试和对黑洞性质的探测。该奖项通过研究生的参与和他们在物理建模、数学分析以及数值和计算方法方面的培训，为科学工作者的发展做出了贡献。更详细地说，与该奖项相关的主要研究工作是：(1)改进了两种精确的数学和数值引力自力方法，以及相关的计算机代码，这些方法有助于计算小质量比和高度偏心轨道的紧凑双星的引力波；(2)使用其中一种方法，对计算的引力波与截然不同和互补的后牛顿方法进行高精度比较；(3)用第二种数值自力方法计算了偏心双星在轨道衰变后期的轨道衰变、引力波发射和合并。

Astronomical observations have shown that virtually all massive galaxies can be expected to have a supermassive black hole residing at their center. Surrounded by dense star clusters, these black holes will frequently capture stars into highly eccentric orbits. A fraction of these stars will be compact objects: stellar mass black holes or neutron stars. As these compact stars orbit, they radiate gravitational waves, causing the orbit to decay and the star to eventually be swallowed by the supermassive black hole. The emitted radiation is potentially observable in future space-based gravitational wave detectors. The theoretical work funded by this award will provide better understanding of the expected signals from highly-eccentric compact merging binaries. Detection of gravitational waves from such extreme-mass-ratio binaries will provide a unique strong-field test of gravity and a probe of the nature of black holes. This award contributes to scientific workforce development through the involvement of graduate students and the training they receive in physical modeling, mathematical analysis, and numerical and computational methods.In greater detail, the primary research efforts associated with this award are: (1) refined development of two accurate mathematical and numerical gravitational self-force methods, and the associated computer codes, that are useful for computing gravitational waves from merging compact binaries with small mass ratios and highly eccentric orbits; (2) using one such method to make highly accurate comparisons of calculated gravitational waves with the distinct and complementary post-Newtonian approach; and (3) using the second numerical self-force method to calculate the orbital decay, gravitational wave emission, and merger of eccentric binaries in the late stages of their orbital decay.