Stellar Dynamics at the Centers of Galaxies

本项目将研究银河系等星系中心超大质量黑洞（SMBH）周围的致密星团和恒星残骸--白色矮星、中子星和黑洞--的动力学演化。主要研究者和合作者最近的工作表明，这样一个密集的黑洞群的演化是由BH之间的引力相遇和SMBH引起的相对论效应之间的复杂相互作用驱动的。该项目将扩展这项工作，使用一种新的计算算法，可以有效地模拟具有大量引力体的系统。第一次将SMBH的自旋效应包括在内;自旋在轨道上引起框架拖曳力矩，以及轨道物体对SMBH施加的反向力矩，改变其自旋方向。进一步的模拟将研究包含残余质量分布的星团，以及包含双黑洞的星团。目标是增加对控制SMBH周围致密星系核长期演化的动力学机制的基本理解，以及评估SMBH捕获紧凑物体的速率，可能产生引力波。计算机代码将在奖励期结束时公开提供。该项目将支持一名研究生的工作，该研究生还将获得超级计算机系统管理方面的技能。主要研究者将在当地的科学咖啡馆场地进行公共宣传演讲。

This project will study the dynamical evolution of dense clusters of stars and stellar remnants - white dwarfs, neutron stars, and black holes - around super-massive black holes (SMBHs) in the centers of galaxies like the Milky Way. Recent work by the Principal Investigator and collaborators has shown that the evolution of such a dense cluster of black holes is driven by a complex interaction between gravitational encounters among the BHs and relativistic effects due to the SMBH. This project will extend that work, using a new computational algorithm that can efficiently simulate systems with larger numbers of gravitating bodies. The effects of spin of the SMBH will be included for the first time; spin induces a frame-dragging torque on the orbits, and an inverse torque exerted by the orbiting bodies on the SMBH, altering its spin direction. Further simulations will study clusters containing a distribution of remnant masses, and clusters containing binary black holes. The goals are to increase fundamental understanding of the dynamical mechanisms that control the long-term evolution of dense galactic nuclei around SMBHs, as well as to evaluate the rate at which compact objects are captured by the SMBH, potentially generating gravitational waves. The computer code will be made publicly available near the end of the award period. The project will support the work of a graduate student, who will also acquire skills in supercomputer system management. The Principal Investigator will give public outreach presentations at a local science café venue.