Theoretical Studies in Gravitation and Astrophysics

LIGO-Virgo科学合作最近报告了首次两次直接探测到引力波(GW)信号，并证明这些事件(GW150914和GW151226)是由双星黑洞的自旋和合并产生的。这一突破标志着GW天文学时代的开始。计划中的研究通过研究引力波的产生、相对论流体力学和相对论磁流体动力学，在广义相对论和天体物理学领域架起了桥梁。连接不同理论主题的一条共同主线是引力的关键作用，特别是相对论引力。该奖项为UIUC的广义相对论研究提供了主要资金，也是对该机构的理论天体物理学总支持的重要组成部分。相当大一部分资金用于本科生、研究生和博士后的教育、培训和支持。这些学生在该项目资助的大部分研究课题上与PI合作。这笔赠款支持加州大学本科生研究体验(REU)团队在计算天体物理学和广义相对论方面的活动。PI的每个本科生、研究生和博士后都接受了大规模计算和科学可视化以及理论物理和天体物理几个不同领域的培训，为他们在广泛的科学和技术领域追求专业生涯做好了准备。开发的计算机算法和数值代码对其他从事计算物理和天体物理工作的小组很有用。通过国际和平研究所及其小组的研究和推广活动，这笔赠款有助于在各级教育中推广使用计算机和可视化工具，以及提高公众对引力物理和天体物理学中一些最新和最令人兴奋的发展的认识。致密天体是研究的主要论坛，而物质在强引力场中的动力学是一个主要主题。一些研究主题包括致密双星(双星黑洞、双星中子星和双星黑洞--中子星)的激发和合并，双星和其他有希望的天体物理源产生的引力波和伴随的电磁信号，引力坍缩，旋转的相对论恒星的稳定性和不稳定恒星的演化和最终命运，伽马射线爆发源，星系和类星体核心合并的超大质量黑洞周围的环绕双星盘，以及包括银河系在内的星系核心中超大质量黑洞周围的暗物质的概况和可观测的结果。这些主题中的大多数代表了理论物理中长期存在的基本问题，需要大规模的计算才能解决。因此，该方法在很大程度上涉及到在并行机上进行大规模计算，以及分析建模。它们既包括初值计算，也包括演化计算，并处理包含黑洞的真空时空以及包含真实物质源、磁场以及电磁辐射和中微子辐射的时空(“多传播者天文学”)。研究结果对天文观测具有重要意义，包括计划用于引力波干涉仪的天文观测，如高级LIGO/VIGO网络、地球同步轨道、KAGRA、PTAS和ELISA卡。

The LIGO-VIRGO Scientific Collaboration recently reported the first two direct detections of gravitational wave (GW) signals and demonstrated that these events (GW150914 and GW151226) were produced by the inspiral and coalescence of binary black holes. This breakthrough marks the beginning of the era of GW astronomy. The planned research bridges the fields of general relativity and astrophysics, by studying the generation of gravitational waves, relativistic hydrodynamics, and relativistic magnetohydrodynamics. A common thread uniting the different theoretical topics is the crucial role of gravitation, especially relativistic gravitation. This award provides major funding for research in general relativity at UIUC and a significant component of the total support in theoretical astrophysics to that institution. An appreciable portion of the funding is devoted to the education, training and support of undergraduate, graduate, and postdoctoral students. These students collaborate with the PI on the majority of research topics funded by the project. The grant supports the activities of the PI's Research Experiences for Undergraduates (REU) team at UIUC in computational astrophysics and general relativity theory. The training that each of the PI's undergraduate, graduate, and postdoctoral students receives in large-scale computations and scientific visualization, as well as in several different areas of theoretical physics and astrophysics, prepares them to pursue professional careers in a broad range of scientific and technical fields. The computer algorithms and numerical codes that are developed are useful to other groups working in computational physics and astrophysics. Through the research and outreach activities of the PI and his group, the grant helps promote the use of computers and visualization tools at all levels of education, as well as the public awareness of some the latest and most exciting developments in gravitation physics and astrophysics.Compact objects provide the principal forum of the studies, and the dynamics of matter in a strong gravitational field is a major theme. Some of the topics for investigation include the inspiral and coalescence of compact binaries (binary black holes, binary neutron stars and binary black hole--neutron stars), the generation of gravitational waves from binaries and other promising astrophysical sources and the accompanying electromagnetic signals, gravitational collapse, the stability of rotating, relativistic stars and the evolution and final fate of unstable stars, gamma-ray burst sources, circumbinary disks around merging supermassive black holes in the cores of galaxies and quasars, and the profile and observable consequences of dark matter around supermassive black holes in galaxy cores, including the Milky Way. Most of these topics represent long-standing, fundamental problems in theoretical physics requiring large-scale computation for solution. Hence the approach involves to a significant degree large-scale computations on parallel machines, as well as analytical modeling. They comprise both initial value and evolution computations and treat vacuum spacetimes containing black holes as well as spacetimes containing realistic matter sources, magnetic fields and both electromagnetic and neutrino radiation ("multimessenger astronomy"). The results have important implications for astronomical observations, including those planned for gravitational wave interferometers, such as the Advanced LIGO/VIRGO network, GEO, KAGRA, the PTAs and eLISA.