Stars, Black Holes, and Disks: Dense Matter Phenomena in 2D Numerical Relativity

恒星、黑洞和圆盘：二维数值相对论中的稠密物质现象

• 批准号: 2110287
• 负责人: Matthew Duez
• 金额: $ 20.47万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2110287&HistoricalAwards=false
• 关键词: Stars; Black; Holes; Disks; Dense

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 great deal can be learned about the extremes of strong gravity, about denser-than-nuclei matter, and even about the origin of heavy elements, by studying the collisions of neutron stars with each other or with black holes. Such a binary system emits gravitational waves as the neutron star and its companion spiral together and electromagnetic waves (visible light, infrared, gamma rays, etc.) after the merger. Both signals are sometimes detectable and in some cases have been detected. Numerical simulations that include general relativity are the only way to predict how merger processes unfold, and they've gotten pretty good at modeling the merger and the first few hundredths of a second afterward. The post-merger evolution lasts around a couple of seconds. Although this does not sound long, it is too long to be accessible to 3D numerical simulations, especially because the presence of small-scale turbulent flows makes the grids needed large and the simulations expensive. This project will probe these later times with numerical relativity, following the story of the merger through to completion, when nothing but a stable, quiescent black hole or neutron star remains. The problems of large grid and long time requirements will be dealt with by carrying out 2D simulations (using the rough symmetry about a rotation axis) and carefully-designed models of the effect of turbulent flows on scales to small to be directly captured on the 2D grids. These simulations will include a high degree of realism in the treatment of magnetic fields and neutrino radiation. The techniques and code developed to carry them out will be applicable to other interesting systems with near-axisymmetry, such as collapsing stars.This award supports long-time (multi-second) studies of these strong-gravity, dense-matter systems using the Spectral Einstein Code (SpEC), a high-accuracy numerical relativity code that includes magnetohydrodynamics, nuclear microphysics, and neutrino transport. SpEC's 2D radiation magnetohydrodynamics code will be improved to include 2D spacetime evolution, Monte Carlo neutrino transport, and a mean-field/large-eddy incorporation of the effects of turbulence in the azimuthal direction. Long-time 2D simulations will extend existing compact binary merger simulations for multiple seconds, yielding accurate predictions about disk winds, winds from and possible delayed collapse of a stellar remnant, and GRB energetics. Finally, these numerical techniques will be applied to the first SpEC simulations of black hole formation and growth in a post-collapse, long-duration GRB scenario.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，并涉及美国国家科学基金会“宇宙之窗”大创意的优先领域。通过研究中子星相互碰撞或中子星与黑洞的碰撞，可以了解很多关于强引力极端情况、比原子核密度更大的物质，甚至重元素起源的知识。 这样的双星系统随着中子星及其伴星螺旋在一起而发射引力波，并在合并后发射电磁波（可见光、红外线、伽马射线等）。 这两种信号有时都是可检测到的，并且在某些情况下已经被检测到。包括广义相对论在内的数值模拟是预测合并过程如何展开的唯一方法，并且他们非常擅长对合并及其后的最初百分之一秒进行建模。合并后的演变持续大约几秒钟。 虽然这听起来并不长，但对于 3D 数值模拟来说太长了，特别是因为小规模湍流的存在使得所需的网格很大并且模拟成本很高。 该项目将用数值相对论来探索这些后期时代，追踪合并的故事直至完成，此时只剩下一个稳定、静止的黑洞或中子星。 大网格和长时间要求的问题将通过进行二维模拟（使用关于旋转轴的粗略对称性）和精心设计的模型来解决，该模型的湍流对小尺度的影响可以直接在二维上捕获网格。 这些模拟将包括高度真实的磁场和中微子辐射处理。 为实现这些目标而开发的技术和代码将适用于其他具有近轴对称性的有趣系统，例如塌缩恒星。该奖项支持使用以下方法对这些强重力、致密物质系统进行长期（多秒）研究谱爱因斯坦代码 (SpEC)，一种高精度数值相对论代码，涵盖磁流体动力学、核微物理和中微子输运。 SpEC 的二维辐射磁流体动力学代码将得到改进，包括二维时空演化、蒙特卡罗中微子输运以及方位角方向湍流效应的平均场/大涡合并。 长时间的二维模拟将把现有的紧凑型双星合并模拟延长数秒，从而对盘风、来自恒星残骸的风和可能的延迟坍缩以及GRB能量产生准确的预测。最后，这些数值技术将应用于第一个 SpEC 模拟，该模拟在塌缩后、长期伽玛暴场景中黑洞的形成和增长。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力评估进行评估，被认为值得支持。优点和更广泛的影响审查标准。

项目成果

Late-time post-merger modeling of a compact binary: effects of relativity, r-process heating, and treatment of transport

• DOI: 10.1088/1361-6382/acc0c6
• 发表时间: 2022-08
• 期刊: Classical and Quantum Gravity
• 影响因子: 3.5
• 作者: Milad Haddadi;Matthew D. Duez;F. Foucart;T. Ramirez;Rodrigo Fernández;Alexander L Knight;Jerred Jesse-Jerre

Simulating magnetized neutron stars with discontinuous Galerkin methods

• DOI: 10.1103/physrevd.105.123031
• 发表时间: 2021-09
• 作者: N. Deppe;F. H'ebert;Lawrence E. Kidder;William Throwe;Isha Anantpurkar;C. Armaza;G. Bonilla;M. Boyle;H. Chaudhary;Matthew D. Duez;Nils L. Vu;F. Foucart;M. Giesler;Jason S. Guo;Yoonsoo Kim;Prayush Kumar;I. Legred;Dongjun Li;G. Lovelace;Sizheng Ma;A. Macedo;D. Melchor;M. Morales;Jordan Moxon;Kyle C. Nelli;É. O’Shea;H. Pfeiffer;T. Ramirez;H. Ruter;Jennifer A. Sanchez;M. Scheel;Sierra Thomas;D. Vieira;Nikolas A. Wittek;T. Włodarczyk;S. Teukolsky

Nonlinear mode-tide coupling in coalescing binary neutron stars with relativistic corrections

• DOI: 10.1103/physrevd.106.083001
• 发表时间: 2021-07
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Fatemeh Hossein Nouri;S. Bose;Matthew D. Duez;A. Das