WoU-MMA: Research in Black Hole Physics and Relativistic Astrophysics

该奖项支持相对论和相对论天体物理学的研究，并解决了NSF“宇宙之窗”大构想的优先领域。这项研究的很大一部分是通过超级计算机模拟来解决爱因斯坦方程的数值问题。这项提议的研究将对我们对基础物理学的理解产生广泛的影响。像LIGO这样的实验才刚刚开始在黑洞强场范围内对广义相对论进行真正的检验。要用观察来对抗理论，人们必须能够计算出理论所预测的东西。LIGO观测到的黑洞是爱因斯坦理论预言的黑洞吗？这项研究将对天文学产生影响。包含中子星的双星系统的合并可以导致电磁和中微子信号的发射，以及引力波。到目前为止，在一个引人注目的案例中，这样的事件已经被LIGO用引力波探测到，而且还跨越了电磁波谱。随着这些事件越来越多，需要更好的模拟来帮助确定这些二进制的参数和这些信号的特征（时间标度，强度等）。这项研究还将对计算科学的更广泛领域产生影响。在这里开发的计算技术可以用于解决许多其他领域的问题，包括流体动力学、气象学、地震学和天体物理学。在这些技术方面受过训练的年轻研究人员需求量很大。相对论和黑洞继续吸引着公众，并使科学得以广泛传播。调查人员制作的模拟电影将继续提供公众宣传。为了解决爱因斯坦的方程，研究人员将使用适合方程数学性质的高精度计算技术。这些方法用比其他技术少得多的计算成本来求解方程。其中一个重点是跟踪双黑洞系统的合并和合并，并计算这些过程发出的引力波形。研究的第二个重点是研究包含一颗中子星和一个黑洞或两颗中子星的双星系统的聚结和合并。研究人员将在模拟中加入更真实的微物理描述，如核物质的状态方程、中微子效应和磁场。研究人员还将为计算天体物理学开发一种新的代码，该代码旨在利用即将到来的百亿亿次机器，这是当前代码无法做到的。这个新代码将基于不连续Galerkin方法和基于任务的并行性。它不仅将为数值相对论提供革命性的能力，而且还将为计算天体物理学中的许多问题提供革命性的能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports research in relativity and relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. A large component of the research is aimed at the numerical solution of Einstein's equations by supercomputer simulations. The proposed research will have a broad impact on our understanding of fundamental physics. The first real tests of general relativity in the strong field regime of black holes are just beginning to occur with experiments like LIGO. To confront theory with observation, one must be able to calculate what the theory predicts. Are the black holes that LIGO observes the black holes predicted by Einstein's theory? The research will have an impact on astronomy. Mergers of binary systems containing neutron stars can lead to the emission of electromagnetic and neutrino signals, as well as gravitational waves. In one spectacular case so far, such an event has been detected by LIGO with gravitational waves, and also all across the electromagnetic spectrum. As more of these events are seen, better simulations are needed to help determine the parameters of these binaries and the characteristics of these signals (timescale, strength, etc.). The research will also have an impact on the broader area of computational science. The computational techniques to be developed here can be used to solve problems in many other areas, including fluid dynamics, meteorology, seismology, and astrophysics. Young researchers trained in these techniques are in great demand. Relativity and black holes continue to fascinate the public and allow science to be communicated broadly. Movies of simulations produced by the investigators will continue to provide public outreach.To solve Einstein's equations, the investigators will use high-accuracy computational techniques suited to the mathematical properties of the equations. These methods solve the equations at a much smaller computational cost than other techniques. One focus is to track the coalescence and merger of binary black hole systems and to calculate the gravitational waveform emitted by such processes. A second focus of the research is to study the coalescence and merger of binary systems containing a neutron star and a black hole, or two neutron stars. The investigators will include ever more realistic descriptions of the microphysics in the simulations, such as the equation of state of nuclear matter, neutrino effects,and magnetic fields. The investigators will also develop a new code for computational astrophysics that is designed to take advantage of upcoming exascale machines in a way that current codes cannot. This new code will be based on discontinuous Galerkin methods and task-based parallelism. It will provide transformative capabilities not only for numerical relativity, but for many problems in computational 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.