Gravitational Waves from Neutron Star and Black Hole Mergers

2015年首次直接探测到引力波是引力物理学的历史性突破。第一个信号被确定为两个黑洞的并合事件，这表明紧密双星的并合确实是引力波源的主要候选者。该提案的重点是涉及中子星的紧双星，无论是中子星双星还是由中子星和黑洞组成的双星，都是由广义相对论与广义相对论流体力学相结合来描述的。合并事件的数据分析和参数估计依赖于在高动态强场状态下解决爱因斯坦广义相对论两体问题的数值模拟。目标是为相对论动力学、抛射体和环面形成的合并过程以及引力波的产生提供理论模型。到目前为止，在数值相对论中主要研究的系统是在准圆形轨道上具有相等或相当质量的非自旋中子星。在最近的工作中，解决了构建双星中子星旋转广义相对论数据的技术限制。该项目的主要目标是极大地扩展第一个具有自旋的原理证明计算。通过改变双星的自旋、质量和离心率，长期目标是完善数值相对论可及的引力参数空间，并为预计在不久的将来进行的相应引力波观测做好准备。

The first direct detection of gravitational waves in 2015 was ahistoric breakthrough in gravitational physics. The first signals wereidentified as merger events of two black holes, which demonstratedthat mergers of compact binaries are indeed primary candidates forgravitational wave sources. The focus of the proposal is on compactbinaries involving neutron stars, either in a neutron star binary or abinary formed by a neutron star and a black hole, which are describedby general relativity coupled to general relativistic hydrodynamics.The data analysis and parameter estimation for merger events rely onnumerical simulations that solve the two-body problem of Einstein'sgeneral theory of relativity in the highly-dynamic strong-fieldregime. The goal is to provide theoretical models for the relativisticdynamics, the merger process with ejecta and torus formation, and thegeneration of gravitational waves. So far, the system that has beenpredominantly studied in numerical relativity is non-spinning neutronstars of equal or comparable mass on quasi-circular orbits. In recentwork technical limitations in constructing general relativistic datafor spinning neutron stars in binaries were resolved. The main goal of theproject is to greatly extend the first proof-of-principle calculationswith spin. By varying the spins, masses and eccentricity of thebinary, the long-term goal is to thereby complete the gravitationalparameter space accessible to numerical relativity and to prepare forthe corresponding gravitational wave observations that are expected inthe near future.