NSF-BSF: Gravitational Waves From Compact Objects at Galactic Nuclei

最近，LIGO和Virgo的引力波探测器直接探测到来自合并双黑洞的引力波，这改变了天文学家观察和理解宇宙的方式。然而，这些像黑洞这样的致密物体是如何聚集在一起并靠近到足以合并的，这仍然是一个悬而未决的问题。一个重要的途径是致密星团的动态形成。加州大学洛杉矶分校和以色列耶路撒冷希伯来大学之间的一项研究合作将研究由星系核或星系中心区域的致密天体双星组成的系统的形成、演化和引力波发射，这些星系拥有宇宙中已知密度最大的一些星团。该项目将包括研究生和本科生参与研究。此外，加州大学洛杉矶分校的首席研究员将实施一个原创的教育研讨会，题为“加州未来的科学领袖（居里），每个人的物理学和天文学（PHASOR）”。这个教育研讨会针对的是洛杉矶少数族裔高中生，将直接影响年轻学生，向他们展示STEM职业道路是向他们开放的。在一项概念验证研究的基础上，研究人员将分析导致或抑制致密天体合并的物理过程，该研究概述了致密星系核心中可能的GW源。这项工作将包括恒星与星系中心超大质量黑洞（SMBH）之间的引力相互作用、广义相对论、引力波发射以及后主序星的演化。该方法将利用长期（即长期，轨道平均）和多体相互作用的统计方法的组合方法，以及直接积分（即n体）效应。特别是，SMBH可以诱导恒星和致密物体（如黑洞和中子星）之间的碰撞和合并。该研究将在LIGO-Virgo和LISA观测的背景下预测星系核处GW源动态形成的结果，并利用这些结果试图解释一些奇异的GW信号，如令人费解的大质量致密天体（如GW190814和GW190521）。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。

Recent direct detections of gravitational waves (GW) from merging binary black holes by the LIGO and Virgo GW detectors have transformed the way astronomers observe and understand the Universe. However, it is still an open question how these pairs of compact objects like black holes come together and get close enough to merge. One important channel is dynamical formation in dense star clusters. A research collaboration between the University of California-Los Angeles and the Hebrew University of Jerusalem in Israel will examine the formation, evolution, and gravitational wave emission of systems composed of compact object binaries in galactic nuclei , or the central regions of galaxies, which host some of the densest known stellar clusters in the universe. The project will include graduate and undergraduate students in the research. Additionally, the UCLA lead investigator will implement an original educational workshop, entitled ``California’s fUtuRe scIence lEaders (CURIE), PHysics & AStronomy for EveRyone (PHASOR)." This educational workshop is aimed at under-represented minority high schoolers in Los Angeles and will directly impact young students, showing them that STEM career paths are open to them. Expanding on a proof-of-concept study that outlined the possible GW sources in dense galactic cores, the researchers will analyze the physical processes that can either lead to or suppress the merger of compact objects. The work will include gravitational interactions between stars and the supermassive black hole (SMBH) at the galaxy center, general relativity, gravitational wave emission, and post-main sequence stellar evolution. The methodology will utilize a combined approach of secular (i.e., long-term, orbit averaged) and statistical approaches of the many-body interaction, as well as direct integration (i.e., N-body) effects. In particular, the SMBH can induce collisions and mergers between stars and compact objects, such as black holes and neutron stars. The study will predict the outcome of the dynamical formation of GW sources at galactic nuclei in the context of LIGO-Virgo and LISA observations and use the results to attempt to explain some of the exotic GW signals, such as the puzzling massive compact objects (e.g., GW190814 and GW190521). 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.