Gravitational Radiation and Relativistic Astrophysics

这是一个关于引力波源的物理和天体物理的研究项目，部分是为了支持激光干涉仪引力波天文台(LIGO)；它将由加州理工学院相对论(CART)小组执行，由陈彦北(PI)、克里斯蒂安·奥特和马克·舍尔(Co-PI)领导。通过数值模拟和分析研究，该项目不仅将为LIGO源提供更准确的模型，还将有助于更深入地了解极端条件下的时空几何和物质行为--在黑洞、中子星附近，特别是当这些极端物体相互碰撞时。这些更精确的模型和更深入的理论见解也将应用于LIGO引力波数据的分析。这个项目将作为年轻物理学家和天体物理学家的训练场，向他们传授各种研究技术。CART的成员还将开展广泛的活动，接触更广泛的科学界和公众。更具体地说，该项目将包括三个方向：(A)通过将分析技术和数值模拟(使用光谱爱因斯坦代码[SPEC])相结合：(I)将产生越来越准确的二元黑洞合并的引力波形，并用于为LIGO产生数值模板库；(Ii)将可视化和探索高度弯曲的时空的几何动力学。(B)SPEC将用于研究具有物质的引力波(GW)源(中子星双星、中子星/黑洞双星)，有助于更深入地了解：(1)它们的GW、中微子和电磁发射，以及(2)它们在约束核状态方程(EOS)方面的使用。新开发的高阶流体力学方法将被纳入SPEC。在此基础上，进行了超长激发态模拟，并与后牛顿理论进行了比较。最近发现的NSNS合并后振荡的EOS依赖性也将在完全广义相对论中进行研究。(C)CART小组将为LIGO科学协作(LSC)检测GW和从检测到的信号中提取信息的努力做出贡献。他们将(I)领导从未来对核心塌缩超新星的GW观测推断物理的努力；(Ii)参与从遥远的核心塌缩超新星寻找GW；(Iii)改进从脉冲星等连续来源探测GW的方法。

This is a research project on the physics and astrophysics of gravitational wave sources, partially in support of the Laser Interferometer Gravitational-wave Observatory (LIGO); it will be carried out by the Caltech Relativity Theory (CaRT) group, led by Yanbei Chen (PI), Christian Ott and Mark Scheel (Co-PIs). Through numerical simulations and analytical studies, this project will not only provide more accurate models for LIGO sources, but will also lead to a deeper understanding of the behavior of space-time geometry and matter under extreme conditions - near black holes, neutron stars, especially when these extreme objects collide with each other. These more accurate models and deeper theoretical insight will also be applied to the analysis of LIGO gravitational-wave data. This project will serve as a training ground for young physicists and astrophysicists, by teaching them a wide variety of research techniques. Members of the CaRT will also pursue a wide range of activities that reach out to the broader scientific community and the general public.More specifically, the project will consists of three directions: (A) By combining analytical techniques and numerical simulations (using the Spectral Einstein Code [SpEC]): (i) Increasingly accurate gravitational waveforms for binary black hole coalescence will be generated and used to produce numerical template banks for LIGO; (ii) The geometrodynamics of highly curved spacetimes will be visualized and explored. (B) SpEC will be applied to the study of gravitational wave (GW) sources with matter (neutron-star binaries, neutron-star/black-hole binaries), contributing to a deeper understanding of: (i) their GW, neutrino, and electromagnetic emissions, as well as (ii) their use in constraining the nuclear Equation of State (EOS). Newly developed higher-order hydrodynamics methods will be incorporated into SpEC. With these, ultra-long inspiral simulations will be carried out and compared to post-Newtonian theory. Recently discovered EOS-dependence of NSNS post-merger oscillations will also be investigated in full general relativity. (C) The CaRT group will contribute to the LIGO Scientific Collaboration's (LSC) efforts to detect GWs and extract information from detected signals. They will (i) lead the effort to infer physics from future GW observations of core-collapse supernovae; (ii) participate in searches for GWs from distant core-collapse supernovae; (iii) improve methods for the detection of GWs from continuous sources such as pulsars.