WoU-MMA: Can Black Hole Images Constrain Modified Gravity Theories?

WoU-MMA：黑洞图像能否约束修正的引力理论？

• 批准号: 2007936
• 负责人: Charles Gammie
• 金额: $ 55.58万
• 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: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2007936&HistoricalAwards=false
• 关键词: WoU; MMA; Black; Hole; Images

The recent imaging of the black hole at the center of the galaxy M87 by the Event Horizon Telescope holds the promise of revealing wonders about the astrophysics of material accreting onto a supermassive black hole. The information contained in these images has promise to also allow for tests of general relativity in the region of strong gravitational fields outside the event horizon of a supermassive black hole. A research group at the University of Illinois at Urbana-Champaign will study whether these images can indeed be used to constrain deviations from Einstein's theory. This research will be integrated with activities aimed at increasing the interest of middle-school students and the general public in physics and science in general. The research plan is aimed at studying whether the images obtained from the observation of the black holes at the center of the galaxy M87 and at the center of the Milky Way can be used to constrain deviations from Einstein's theory of general relativity. First, the investigators will study how the shape of the so-called shadow in these images changes in modified gravity, developing a fit for the boundary and calculating the Lyapunov exponents of unstable geodesics near the light-ring, which produce certain features in the image. Then, they will develop simple, phenomenological models of accretion flow in modified gravity, which will allow them to generate simple synthetic images and study the effect of deviations from general relativity. This study will be followed by an analysis of the Blandford-Znajek process in modified gravity to test how sensitive the jet power and magnetic field structure are to departures from general relativity. The project will conclude with a thorough treatment of general relativistic magnetohydrodynamics and accretion in modified gravity, and the generation of synthetic polarized images from realistic accretion models to determine whether deviations from general relativity can be disentangled from other astrophysical processes. This project advances the goals of the NSF Windows on the Universe Big Idea.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.

事件视界望远镜最近对M87星系中心黑洞的成像有望揭示有关物质吸积到超大质量黑洞上的天体物理学奇迹。这些图像中包含的信息也有望在超大质量黑洞事件视界外的强引力场区域进行广义相对论的测试。伊利诺伊大学厄巴纳-香槟分校的一个研究小组将研究这些图像是否真的可以用来限制爱因斯坦理论的偏差。 这项研究将与旨在提高中学生和一般公众对物理和科学的兴趣的活动相结合。该研究计划旨在研究通过观测M87星系中心和银河系中心的黑洞所获得的图像是否可以用来约束对爱因斯坦广义相对论的偏离。首先，研究人员将研究这些图像中所谓阴影的形状如何在修改后的重力下变化，开发边界拟合并计算光环附近不稳定测地线的李雅普诺夫指数，这会在图像中产生某些特征。然后，他们将在修改后的引力中开发简单的吸积流唯象模型，这将使他们能够生成简单的合成图像，并研究偏离广义相对论的影响。这项研究之后将分析修正重力中的布兰德福德-兹纳杰克过程，以测试喷流功率和磁场结构对偏离广义相对论的敏感程度。该项目最后将彻底处理广义相对论磁流体动力学和修正引力中的吸积，并从现实的吸积模型生成合成偏振图像，以确定是否可以从其他天体物理过程中摆脱对广义相对论的偏离。 该项目推进了NSF宇宙大创意窗口的目标。该奖项反映了NSF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。

项目成果

Spherical Accretion in Alternative Theories of Gravity

• DOI: 10.3847/1538-4357/ac3a03
• 发表时间: 2021-11
• 期刊: The Astrophysical Journal
• 作者: A. Bauer;A. C'ardenas-Avendano;C. Gammie;N. Yunes

iharm3D: Vectorized General Relativistic Magnetohydrodynamics

• DOI: 10.21105/joss.03336
• 发表时间: 2021-10
• 期刊: J. Open Source Softw.
• 作者: B. Prather;G. Wong;Vedant Dhruv;B. Ryan;J. Dolence;S. Ressler;C. Gammie

PATOKA: Simulating Electromagnetic Observables of Black Hole Accretion

• DOI: 10.3847/1538-4365/ac582e
• 发表时间: 2022-02
• 期刊: The Astrophysical Journal Supplement Series
• 作者: G. Wong;B. Prather;Vedant Dhruv;B. Ryan;M. Mościbrodzka;Chi-kwan Chan;A. Joshi;R. Yarza

Blandford-Znajek process in quadratic gravity

• DOI: 10.1103/physrevd.105.044008
• 发表时间: 2021-11
• 期刊: Physical Review D
• 影响因子: 5
• 作者: J. Dong;N. Patino;Yiqi Xie;A. C'ardenas-Avendano;C. Gammie;N. Yunes