Collaborative Research: Simulating Neutron Star---Black Hole Inspirals: From Binaries to Accretion and Jets

吸积黑洞双星系统（ABHB）是由一颗恒星绕着一个小黑洞旋转组成的。 一个特别有趣的例子是中子星-黑洞（NS-BH）双星，它可能是引力波观测站（如高级LIGO）的引力波源。 来自NS-BH双星的引力和电磁波信号包含了关于双星特殊演化的信息，包括磁效应和黑洞潮汐力对中子星的破坏。该奖项支持研究ABHB和相关系统的计算基础设施和技术的发展。 这包括进一步发展的HAD，一个免费提供的，模块化的计算工具包求解微分方程在分布式并行环境。 HAD提供了复杂的自适应网格细化功能，允许用户联合收割机结合不同类型的微分方程和/或数值方法。 为满足ABHB系统模拟和提取有价值的物理信息的需要，将进一步发展和实现求解Einstein方程和磁流体动力学（MHD）方程的技术。这项工作有助于推进一个重要科学问题的数值技术，以及分布式计算的先进工具的创建和传播。 基础设施的模块化设计允许其他研究人员共享和扩展这些工具。 最后，本研究涉及博士后研究人员、研究生和本科生的培养。

An accreting black hole binary system (ABHB) consists of a starorbiting a small black hole. One particularly interesting exampleis a neutron star-black hole (NS-BH) binary, which may be interestingsources of gravitational waves for gravitational wave observatories suchas Advanced LIGO. The gravitational and electromagnetic wave signalsfrom NS-BH binaries contains information about the particular evolution ofthe binary, including magnetic effects and the disruption of the neutronstar by the tidal forces of the black hole.This award supports the development of computational infrastructure andtechniques to study ABHBs and related systems. This includes the furtherdevelopment of HAD, a freely available, modular computational toolkit forsolving differential equations in a distributed parallel environment. HADprovides sophisticated adaptive mesh refinement capabilities, which allowthe user to combine different types of differential equations and/ornumerical methods. Techniques for solving the Einstein equations andmagnetohydrodynamics (MHD) equations will be further developed andimplemented in the code to meet the demands of simulating ABHB systems andextracting valuable physical information. This work serves to advance numerical techniques for an important scientificproblem, as well as the creation and dissemination of advanced tools fordistributed computing. The modular design of the infrastructure allowsother researchers to share and extend these tools. Finally, this studyinvolves the training of postdoctoral researchers, graduate students, andundergraduates.