Orbiting binary black holes - From the post-Newtonian regime to the innermost stable circular orbit by combining initial data sequences and numerical evolutions

NSF的LIGO引力波探测器是世界各地许多新的和计划中的设施之一，旨在直接探测和测量引力波。引力波的观测将为我们打开一扇了解宇宙的新窗口，使我们能够以完全不同的方式研究黑洞、超新星、中子星、超新星和伽马射线爆发等奇异物体。该项目的工作旨在继续开发一种通用数字代码，能够模拟预计最重要的引力辐射源之一，即由黑洞组成的双星系统。该项目的具体重点是通过以下方式改进这种双黑洞模拟：（i）为模拟提供更现实的初始条件;（ii）提高模拟的质量和准确性;（iii）研究周期驻波近似等近似方案的有效性和实用性。这项工作很重要，因为只有从现实初始条件开始的准确模拟，将能够产生可靠的理论预测的引力波将在不久的将来观察到。此外，这项研究为协同努力做出了关键贡献，从数值和数学相对论到引力波天体物理学。它是与位于布朗斯维尔的德克萨斯大学和德国的耶拿大学的相对论小组合作进行的。定期交流使这三个机构的学生受益。

The NSF's LIGO gravitational wave detectors are among a number of new and planned facilities all over the world which are designed to directly detect and measure gravitational waves. The observation of gravitational waves will open a new window on the universe by enabling us to study exotic objects such as black holes, supernovae, neutron stars, collapsars and gamma-ray bursts in a completely different way. The work in this project is aimed at continuing the development of a generic numerical code capable of simulating what is expected to be one of the most important sources of gravitational radiation, namely binary systems consisting of black holes. The specific focus of this project is to improve such binary black hole simulations by (i) providing more realistic initial conditions for the simulations, (ii) improving the quality and accuracy of the simulations and (iii) studying the validity and utility of approximation schemes such as the periodic standing-wave approximation.This work is important because only accurate simulations, which start from realistic initial conditions, will be able to produce reliable theoretical predictions of the gravitational waves which will be observed in the near future. In addition, this investigation makes key contributions to synergistic efforts, ranging from numerical and mathematical relativity to gravitational wave astrophysics. It is carried out in collaboration with the relativity groups at the University of Texas in Brownsville and the University of Jena in Germany. Regular exchanges benefit students from all three institutions.