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

最近，LIGO和室女座GW探测器对合并的双星黑洞产生的引力波(GW)进行了直接探测，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天体是如何聚集在一起并足够近地合并的，仍然是一个悬而未决的问题。致密星团中的动力形成是一个重要的通道。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检查由星系核或星系中心区域的致密物体双星组成的系统的形成、演化和引力波发射，这些星系拥有一些宇宙中已知的最密集的星团。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)，每个人的物理学与天文学(PHASOR)。这一教育研讨会针对的是洛杉矶人数不足的少数族裔高中生，并将直接影响年轻学生，向他们展示STEM的职业道路对他们开放。在一项概念验证研究的基础上展开，该研究概述了致密星系核心中可能存在的GW源，研究人员将分析可能导致或抑制致密天体合并的物理过程。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、引力波发射和主序后恒星演化。该方法将采用长期(即长期、轨道平均)和统计方法相结合的多体相互作用方法，以及直接综合(即N体)效应。特别是，SMBH可以引起恒星与致密天体之间的碰撞和合并，如黑洞和中子星。这项研究将在LIGO-Virgo和LISA观测的背景下预测星系核GW源动态形成的结果，并试图用这一结果来解释一些奇异的GW信号，例如令人费解的大质量致密天体(例如GW190814和GW190521)。这个项目推进了NSF宇宙大理想之窗的目标。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.