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Theoretical Studies in Gravitation and Astrophysics

引力和天体物理学的理论研究

基本信息

批准号：
2006066
负责人：
Stuart Shapiro
金额：
$ 51万
依托单位：
University of Illinois at Urbana-Champaign
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2006066&HistoricalAwards=false
关键词：
Theoretical Studies Gravitation Astrophysics

项目摘要

This award supports research in relativity and relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. The LIGO/Virgo Scientific Collaboration has compiled an impressive list of detected gravitational wave (GW) events consisting of several dozen binary black hole (BHBH) mergers, a couple of binary neutron star (NSNS) mergers and several likely black hole--neutron star (BHNS) mergers. These detections mark the beginning of the era of GW astronomy. This research project spans several problems involving general relativity (GR), the generation of GWs, relativistic hydrodynamics, and relativistic magnetohydrodynamics. A common thread uniting the different theoretical topics is the crucial role of gravitation, especially relativistic gravitation. Compact objects (black holes, neutron stars and white dwarfs) provide the principal forum, 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 (BHBHs, NSNSs and BHNSs); the generation of GWs from merging binaries and other promising astrophysical sources, and their counterpart electromagnetic (EM) signals; gravitational collapse; the stability of rotating, relativistic stars and the evolution and final fate of unstable stars; gamma-ray burst sources (GRBs); the formation and growth of supermassive black holes (SMBHs) from the magnetorotational collapse of supermassive stars (SMSs) and other scenarios; circumbinary disks around merging binary SMBHs in the cores of galaxies and quasars; and the profiles and observable signatures of dark matter around SMBHs in galaxy cores, including the Milky Way, and the dynamical evolution of clusters containing DM, stars and SMBHs. The results have important implications for astronomical observations, including those collected by and/or planned for GW interferometers.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 simulations on supercomputers, in addition to analytical modeling. The key tool will be the robust and well-tested Illinois general relativistic, magnetohydrodynamic (GRMHD) code. The simulations solve Einstein's field equations of GR for gravity coupled to the equations of relativistic MHD for the fluid and Maxwell's equations for the EM fields. These equations constitute highly nonlinear, coupled partial differential equations in 3+1 dimensions that are solved by finite-differencing. The Illinois GRMHD code employs the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) technique with moving puncture gauge conditions and adaptive moving mesh refinement to solve the field equations and a high-resolution, shock capturing scheme for the MHD. The problems to be tackled 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 EM and neutrino radiation ("multimessenger astronomy"). The research and outreach activities supported by this grant help 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 gravitational physics and astrophysics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项支持相对论和相对论天体物理学的研究，并阐述了美国国家科学基金会“宇宙之窗”宏伟构想的优先领域。LIGO和处女座的科学合作编制了一份令人印象深刻的探测到的引力波(GW)事件清单，其中包括数十个双星黑洞(BHBH)合并，几个双星中子星(NSNS)合并和几个可能的黑洞-中子星(BHNS)合并。这些探测标志着GW天文学时代的开始。这个研究项目跨越了几个问题，涉及广义相对论(GR)、GW的产生、相对论流体力学和相对论磁流体动力学。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。致密天体(黑洞、中子星和白矮星)提供了主要的论坛，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(BHBHs、NSNSS和BHNSS)的激发和合并；合并双星和其他有希望的天体物理源的产生GW，以及它们对应的电磁(EM)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(GRb)；超大质量恒星(SMSs)的磁致旋转坍塌(SMBHs)和其他情况下形成和增长的超大质量黑洞(SMBHs)；星系和类星体核心中合并的双星SMBHs周围的双星圆盘；以及包括银河系在内的星系核中SMBH周围暗物质的轮廓和可观测的特征，以及包含DM、恒星和SMBH的星系团的动力学演化。这些结果对天文观测具有重要的意义，包括由GW干涉仪收集和/或计划用于GW干涉仪的天文观测。这些主题中的大多数都是理论物理中长期存在的基本问题，需要大规模计算才能解决。因此，除了分析建模之外，该方法还在很大程度上涉及到在超级计算机上进行大规模模拟。关键工具将是强大且经过充分测试的伊利诺伊州广义相对论、磁流体力学(GRMHD)代码。模拟求解了爱因斯坦的重力GR场方程，流体的相对论MHD方程和电磁场的麦克斯韦方程。这些方程构成了3+1维的高度非线性、耦合的偏微分方程组，可用有限差分法求解。伊利诺伊州GRMHD程序使用Baumgarte-Shapiro-Shibata-Nakamura(BSSN)技术和移动穿透量规条件和自适应移动网格加密来求解场方程和高分辨率的MHD激波捕获方案。要解决的问题包括初值和演化计算，以及处理包含黑洞的真空时空，以及包含真实物质源、磁场以及电磁场和中微子辐射的时空(“多信使天文学”)。这笔赠款支持的研究和推广活动有助于在各级教育中促进计算机和可视化工具的使用，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。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。