The First Multi-Messenger Study of Supermassive Black Hole Growth

约瑟夫·西蒙被授予美国国家科学基金会天文学和天体物理学奖学金，在科罗拉多大学开展研究和教育计划。 结合脉冲星定时阵列（PTA）对引力波（GW）背景的测量和星系合并的电磁观测，西蒙将模拟黑洞（BH）如何合并形成超大质量黑洞（SMBH）。 该项目的结果将使天文学家能够更好地了解SMBH的质量如何增长。 西蒙还将为本科生提供研究指导，并让他们参与到资源丰富的社区服务的当地中学和高中的外联活动计划中。出现在PTA数据中的GW背景的暗示似乎与忽略BH-BH合并的贡献的理论预测不一致，并暗示SMBHs比以前认为的更大规模，或更频繁地合并。 在这个项目中，西蒙将把星系合并和SMBH质量函数的最佳观测结果以及双星演化时间尺度的新处方纳入他的双星SMBH人口和GW背景的建模框架中。他将首先使用他的精炼模型从PTA数据中提取二进制演化时间尺度。然后，他将联合收割机结合星系合并的电磁观测和SMBH质量函数与PTA观测，进行由于BH-BH合并导致的SMBH质量增长的首次多信使测量。 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。

Joseph Simon is awarded an NSF Astronomy and Astrophysics Fellowship to carry out a program of research and education at the University of Colorado. Combining pulsar timing array (PTA) measurements of the gravitational wave (GW) background with electromagnetic observations of galaxy mergers, Simon will model how black holes (BH) merge to form supermassive black holes (SMBH). Results from this project will allow astronomers to better understand how SMBH grow in mass. Simon will also provide research mentoring to undergraduate students and engage them in a program of outreach activities to local middle schools and high schools serving under resourced communities. Hints of the GW background emerging in PTA data appear inconsistent with theoretical predictions neglecting the contributions from BH-BH mergers and imply that SMBHs are more massive, or merge more frequently than previously thought. In this project, Simon will incorporate the best available observations of galaxy mergers and the SMBH mass function alongside a new prescription for the binary evolution timescale into his modeling framework for the binary SMBH population and the GW background. He will first use his refined models to extract the binary evolution timescale from PTA data. He will then combine the electromagnetic observations of galaxy mergers and the SMBH mass function with PTA observations to conduct the first multi-messenger measurement of SMBH mass growth due to BH-BH mergers. 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.