WoU-MMA: Collaborative Research: Supermassive Binary Black Hole Mergers: Accretion Dynamics and Electromagnetic Output

超大质量黑洞（SMBH）的合并是宇宙中最引人注目的现象之一。在几个小时内，它们以引力波的形式发出的能量相当于宇宙中所有恒星发出的光。然而，还没有人被当场发现，部分原因是没有人知道它们应该在引力波的同时发出什么样的光。该项目将SMBH双星的天体物理学知识与详细的气体流动物理模拟和随时间时空的明确计算相结合，以预测观测者应该寻找的光。初级研究人员将学习这个新领域和非常大规模的计算，加强技术队伍。pi的辅助工作加强了各自大学的教学计划，并为公众宣传做出了贡献。该小组已经建立了做出这些预测所需的知识库和计算方法，包括建立一个多补丁模拟基础设施来计算变化的时空，并允许对子区域进行单独处理。代码库包括后处理工具，将流体模拟数据转换为光子辐射的预测，考虑主要的辐射机制、不透明性和光子在动态时空中的传播。本研究从合并前立即开始，了解其物理机制并准备现实的初始数据。第二步将计算物质在合并阶段和随后的弛豫阶段的行为。然后后处理机器预测EM光谱和光曲线。这个项目推进了NSF宇宙大构想窗口的目标。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。

Supermassive black hole (SMBH) mergers are one of the most dramatic phenomena in the Universe. For a few hours, they can emit as much power in gravitational waves as all the stars in the Universe produce in light. However, none has yet been caught in the act, partly because no one knows what sort of light they should emit along with the gravitational waves. This project combines astrophysical knowledge of SMBH binaries with detailed physical simulation of gas flows and explicit computation of time-dependent spacetimes, to predict the light observers should search for. Junior researchers will learn about this new field and about very large-scale computation, strengthening the technical workforce. Ancillary efforts by the PIs enhance the teaching program at each of their universities and contribute to public outreach.This group has built the knowledge base and computational methods needed to make these predictions, including building a multi-patch simulation infrastructure to compute the changing spacetime and permit separate treatment of subregions. The code base includes post-processing tools that transform fluid simulation data into predictions of photon radiation, accounting for the principal radiation mechanisms, opacities, and photon propagation through dynamical spacetimes. This study starts at the immediate pre-merger state, to understand its physical mechanisms and to prepare realistic initial data. The second step will compute how matter behaves during the merger proper and the subsequent relaxation phase. The post-processing machinery then predicts EM spectra and light curves. 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.