Radiation GRMHD with Non-Thermal Particle Acceleration: Next-Generation Models of Black Hole Accretion Flows and Jets

射电望远镜揭示的最引人注目的现象之一是相对论性喷流，它可以延伸超过100万秒差距，并已被证明与巨型椭圆星系中心的超大质量黑洞（SMBH）有物理联系。尽管经过几十年的努力，我们对气体在自旋SMBH上的吸积过程的理解仍然是不完整的，它被准直成一束狭窄的磁化电子束，并以近光速发射。广义相对论磁流体动力学（GRMHD）流体模拟最近显示出能够正确解释相关物理的希望，并成功地再现了低光度活动星系核（AGN）中的喷流功率和结构，以及预测事件视界望远镜的M87和Sgr A* 图像。首席研究员将领导一个团队，开发适用于更大范围AGN光度的下一代GRMHD代码，将喷流的多波长观测与中央SMBH及其附近环境的特性联系起来。该奖项还将支持在国家的最先进的计算技术的博士后培训，为本科生研究提供机会，并开发公共天文馆显示。所有GRMHD模型和源代码都将公开，下一代GRMHD模型将用于预测广泛的低光度吸积流和喷流的射电到伽马射线发射。这些将被用来解决长期存在的问题，热吸积流的结构，包括相对论性电子如何加载到射流，使他们辐射能量的基本问题。电子分布函数将使用粒子加速的动力学处方和辐射冷却的频率依赖性蒙特卡罗方法来演化。GRMHD模拟将运行足够长的时间，以建立距离黑洞约100个引力半径的平衡特性，以便可靠地预测吸积流和喷流结构。宽带频谱和极化无线电发射图计算从模拟作为一个函数（例如）质量吸积率将与代表性源的观测结果进行比较，并用于预测下一代长基线射电干涉仪的黑洞阴影可见度。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。

One of the most striking phenomena revealed by radio telescopes are relativistic jets that can stretch over a million parsecs and have been shown to be physically connected with supermassive black holes (SMBH) in the centers of giant elliptical galaxies. Despite decades of effort, our understanding of the steps by which gas accreting onto a spinning SMBH is collimated into a narrow, magnetized beam of electrons and launched at near light-speed is still incomplete. General Relativistic Magneto-Hydrodynamic (GRMHD) fluid simulations have lately shown promise in being able to correctly account for the relevant physics and have successfully reproduced jet power and structure in low-luminosity active galactic nuclei (AGN), as well as predicting the Event Horizon Telescope's images of M87 and Sgr A*. The principal investigator will lead a team that will develop next-generation GRMHD code appropriate for a wider range of AGN luminosities that will link multi-wavelength observations of jets to properties of the central SMBH and its near environment. The award will also support the training of a postdoc in state-of-the-art computational techniques, provide opportunities for undergraduate research, and develop public planetarium shows. All GRMHD models and source code will be made publicly available.The next-generation GRMHD models will be used to predict radio to gamma-ray emission from a broad range of low-luminosity accretion flows and jets. These will be used to address longstanding questions about the structure of hot accretion flows, including the fundamental question of how relativistic electrons are loaded into jets causing them to radiate energy. The electron distribution function will be evolved using kinetic prescriptions for particle acceleration and a frequency- dependent, Monte Carlo method for radiative cooling. GRMHD simulations will be run for a sufficiently long duration to establish equilibrium properties up to ~100 gravitational radii from the black hole, in order to reliably predict the accretion flow and jet structure. Broadband spectra and polarized radio emission maps computed from the simulations as a function of (e.g.) mass accretion rate will be compared to observations of representative sources and used to make predictions for the visibility of the black hole shadow for next-generation long baseline radio interferometers.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.