Black Hole - Neutron Star mergers: Theoretical Modeling, Numerical Simulations, and Data Interpretation

引力波的首次直接探测开创了天文学的新纪元。从那时起，已经探测到了许多紧密的双星合并，其中包括黑洞与中子星碰撞发出的引力波。这样的黑洞-中子星系统可以揭示物质在超核密度下的状态信息，或者允许更精确地测量哈勃常数。正因为如此，在理论模型和观测数据之间实现准确的互相关是至关重要的。这需要对黑洞-中子星合并、发出的引力波信号和潜在的电磁对应物进行可靠的理论描述。不幸的是，可用于黑洞-中子星系统的数值相对论模拟的数量很少，针对这类系统的相应波形模型还处于起步阶段。在这个研究项目中，我们计划填补这些空白。为此，我们将扩展伪谱代码椭圆的代码基础设施，以允许构建准确的黑洞-中子星初始数据。这些数据将与BAM程序一起演变，我们的新模拟结果将成为发展新的引力波模型和对盘质量和抛射流出的唯象估计的基础。我们计划将我们的所有结果和代码公开。

The first direct detection of gravitational waves inaugurated a new era in astronomy. Since then numerous compact binary mergers have been detected, among them gravitational waves emitted from the collision of a black hole with a neutron star. Such black hole - neutron star systems can reveal information about the state of matter at supranuclear densities or allow for a more precise measurement of the Hubble constant. Because of this, it is essential to enable an accurate cross-correlation between theoretical models and observational data. This requires a reliable theoretical description of the black hole - neutron star coalescence, the emitted gravitational-wave signal, and potential electromagnetic counterparts. Unfortunately, the number of available numerical-relativity simulations for black hole - neutron star systems is small and the corresponding waveform models for this class of systems are in their infancy. Within this research project, we plan to fill these gaps. For this purpose, we will extend the code infrastructure of the pseudo-spectral code Elliptica to allow the construction of accurate black hole - neutron star initial data. These data will be evolved with the BAM code and our new simulation results will be the fundament for the development of new gravitational-wave models and phenomenological estimates of the disk mass and ejecta outflows. We plan to make all our results and codes publicly available.