WoU-MMA: Mapping the host galaxies of low-frequency gravitational-wave sources

引力波是爱因斯坦将引力描述为扭曲时空的基本预测。就像电磁波一样，引力波信号的频谱可以来自多种来源。虽然地球上的探测器已经观测到质量与太阳相似的黑洞合并产生的引力波，但质量更大的黑洞的合并仍然难以捉摸。然而，通过利用银河系中脉冲星的精确定时活动，我们越来越接近打造银河尺度的探测器，可以测量来自宇宙中最大质量黑洞的引力波信号。该研究小组将创建一个可能包含此类大质量黑洞对的星系目录。这将使研究人员能够将引力波搜索发现的可能的天空位置引用回该目录，并更精确地确定信号的来源。该项目将资助两名多信使科学研究生的培训。 它将产生一个学生开发的网络工具，用于检查和过滤来自 SMBHB 的引力波信号的候选主星系。该网络工具将作为天体物理学研究员 NANOGrav 学生团队 (STARS) 计划的综合活动进行测试和改进。该团队位于范德比尔特大学和加州大学伯克利分校，将为超大质量黑洞双星（SMBHB）系统的多信使发现开辟途径，并构建低频随机引力波（GW）背景的观测驱动模型。这项工作基于来自广域红外巡天探测器的两个大质量星系目录；一个目录是全天空的，但只覆盖到 z0.45，另一个目录是 z1 的，但只有部分天空覆盖。在加州大学伯克利分校，团队成员将开展一项增强和增强计划，为多信使研究提供关键数据，包括星系恒星质量和驻留超大质量黑洞质量。在范德比尔特，团队成员将在不久的将来的脉冲星定时阵列活动中进行模拟发现单个 SMBHB 的现实计划，然后筛选包含在 GW 统计本地化区域内的潜在宿主星系。这将产生一组基于 Galaxy 和 GW 推断的 SMBHB 属性的主机排名协议。在该项目的最后阶段，整个团队将结合他们的专业知识，根据统计权重用 SMBHB 填充增强型目录中的星系。他们将利用这些来制作 GW 天空图，研究集合背景信号角功率分布的各向异性，并探索其对近期信号探测前景的影响。 该奖项解决/推进了“宇宙之窗”大创意的目标。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Gravitational waves are a fundamental prediction of Einstein’s description of gravity as warped spacetime. Just like electromagnetic waves, there is a spectrum of gravitational-wave signals that can originate from a plethora of sources. While gravitational waves have been observed with Earth-based detectors from mergers of black holes similar in mass to the Sun, the mergers of more massive black holes remain elusive. However, by harnessing precision timing campaigns of pulsars in the Milky Way, we are getting closer to forging Galaxy-scale detectors that can measure gravitational-wave signals from the most massive black holes in the Universe. This research team will create a catalog of galaxies that might contain such pairs of massive black holes. This will allow researchers to reference likely sky-locations found by gravitational-wave searches back to this catalog and determine the origin of the signal much more precisely. This project will fund the training of two graduate students in multi-messenger science. It will result in a student-developed web-tool for the inspection and filtering of candidate host-galaxies of gravitational-wave signals from SMBHBs. This web-tool will be tested and improved as an integrated activity for the NANOGrav Student Teams of Astrophysics ResearcherS (STARS) program. Located at Vanderbilt University and UC Berkeley, the team will forge pathways to the multi-messenger discovery of supermassive black-hole binary (SMBHB) systems and construct observationally-driven models of the low-frequency stochastic gravitational wave (GW) background. This work is based on two massive-galaxy catalogs derived from the Wide-field Infrared Survey Explorer; one catalog is all-sky but only complete out to z0.45, the other probes z1 but with only partial sky coverage. At UC Berkeley, team members will conduct a program of augmentation and enhancement to provide crucial data for multi-messenger studies, including galaxy stellar masses and resident supermassive blackhole masses. At Vanderbilt, team members will conduct a realistic program of simulated discoveries of individual SMBHBs in near-future pulsar-timing array campaigns, followed by the filtering of potential host galaxies that are contained within the GW statistical localization regions. This will result in a set of host ranking protocols based on galaxy and GW-inferred SMBHB properties. In the project’s final stage, the full team will combine their expertise to populate galaxies in the enhanced catalogs with SMBHBs according to statistical weights. They will use these to make maps of the GW-sky, study the anisotropy of the ensemble background signal’s angular power distribution, and explore its effect on near-future signal detection prospects. This award addresses/advances the goals of the 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.