Dynamics of fast spinning neutron stars around a black hole

强束缚引力系统常常表现出有趣的动力学现象。在重力作用下旋转有限大小的物体不会遵循时空流形中的测地线。快速旋转的中子星或围绕黑洞运行的中子星双星系统，由于各种相对论性耦合，会表现出复杂的自旋和轨道行为。本项目研究了这类系统的两种特殊类型：(1)围绕黑洞运行的快速旋转NS系统，以及(2)围绕黑洞运行的双中子星系统（这是一个分层三体系统）。(1)自旋曲率耦合导致非平面NS轨道，以及中子星自旋的de-Sitter和lens - thirring进动。(2)轨道-轨道耦合诱导引力磁性，表现在双中子星系统复杂的轨道和自旋运动中。射电脉冲星计时和引力波观测将能够研究这些系统的动力学特性。黑洞-中子星系统在基础物理学和天体物理学的研究中是有用的。它们可以用来绘制黑洞周围的时空结构，并确定星系中大质量核黑洞的质量和自旋。这是一个理论项目。它涉及现象学建模、代数计算和数值计算。

Strongly bound gravitational systems often show interesting dynamical phenomena. Spinning finite-size objects in gravity would not follow geodesics in a space-time manifold. A fast spinning neutron stars or a neutron-star binary system orbiting around a black hole would exhibit complex spin and orbital behaviours due to various relativistic coupling. This project investigates two special classes of such systems: (1) a fast spinning NS orbiting around a BH, and (2) a double neutron-star system orbiting around a BH (which is a hierarchical 3-body system). In (1) spin-curvature coupling leads to non-planar NS orbits, in addition to de-Sitter and Lense-Thirring precessions of the neutron star's spin. In (2) orbit-orbit coupling induces gravito-magnetism, which manifests in the complex orbital and spin motion of the double neutron-star system. Radio pulsar timing and gravitational wave observations will be able to study the dynamical properties of these systems. Black hole - neutron star systems are useful in the study of fundamental physics and in astrophysics. They can be used to map the space-time structure around black holes and to determine the masses and spins of the massive nuclear black holes in galaxies. This is a theoretical project. It involves phenomenological modelling, algebraic computation and numerical calculations.