Secure methods for identifying the host galaxies of individual massive black hole (MBH) binaries and mergers detected by gravitational-wave experiments such as the Laser Interferometer Space Antenna and pulsar timing arrays are currently lacking, but will be critical to a variety of science goals. Recently, in Bardati et al., we used the Romulus25 cosmological simulation to show that MBH merger host galaxies have unique morphologies in imaging, due to their stronger bulges. Here, we use the same sample of simulated MBH merger host galaxies to investigate their stellar kinematics, as probed by optical integral field unit (IFU) spectroscopy. We perform stellar population synthesis and dust radiative transfer to generate synthetic 3D optical spectral data cubes of each simulated galaxy, and produce mock stellar kinematic maps. Based on a linear discriminant analysis of a combination of kinematic parameters derived from these maps, we show that this approach can identify MBH binary and merger host galaxies with accuracies that increase with chirp mass and mass ratio. For mergers with high chirp masses (≳108.2M⊙) and high mass ratios (≳0.5), the accuracies reach ≳85%, and their host galaxies are uniquely characterized by slower rotation and stronger stellar kinematic misalignments. These kinematic properties are commonly associated with massive early-type galaxies that have experienced major mergers, and naturally act as signposts for MBH binaries and mergers with high chirp masses and mass ratios. These results suggest that IFU spectroscopy should also play a role in telescope follow-up of future MBH binaries and mergers detected in gravitational waves.

中文翻译：

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来自宇宙学模拟的大质量黑洞合并宿主星系的特征。II. 积分场单位光谱中独特的恒星运动学


目前缺乏识别单个大质量黑洞 （MBH） 双星和引力波实验（如激光干涉仪空间天线和脉冲星授时阵列）检测到的合并宿主星系的安全方法，但对于各种科学目标至关重要。最近，在 Bardati 等人中，我们使用 Romulus25 宇宙学模拟来证明 MBH 合并宿主星系在成像中具有独特的形态，因为它们的凸起更强。在这里，我们使用模拟 MBH 合并宿主星系的相同样本来研究它们的恒星运动学，如光学积分场单元 （IFU） 光谱所探测的那样。我们进行恒星种群合成和尘埃辐射传输，以生成每个模拟星系的合成 3D 光谱数据立方体，并生成模拟恒星运动图。基于对从这些映射中得出的运动学参数组合的线性判别分析，我们表明这种方法可以识别 MBH 双星系和合并宿主星系，其精度随啁啾质量和质量比的增加而增加。对于具有高啁啾质量 （≳108.2M⊙） 和高质量比 （≳0.5） 的合并，精度达到 ≳85%，它们的宿主星系具有较慢的旋转和更强的恒星运动学错位的独特特征。这些运动学特性通常与经历过重大合并的大质量早期星系有关，并自然而然地成为具有高啁啾质量和质量比的 MBH 双星和合并的路标。这些结果表明，IFU 光谱学也应在望远镜跟踪未来 MBH 双星和引力波中检测到的合并中发挥作用。