Morphology of coalescing BBH waveforms are affected by its spins. Waveform models built for inference of source parameters have several in-built approximations. In current precessing IMRPhenom and SEOBNR waveform models, systems with the same spin magnitude but varying orientation of spins projected on the orbital plane are effectively mapped to the same system (bar an overall phase change) and the asymmetry due to precession between the $+m$ and $-m$ modes is not modelled. In this study, we investigate the validity of these approximations by generating numerical relativity (NR) simulations of single-spin NR systems with varying in-plane spin directions (including several superkick configurations) and provide an estimate of the SNR at which the effect of varying in-plane spin directions would be measurable. This is done computing the match between these waveforms and using these match values to estimate the distinguishability SNR. We also use NR waveforms with different spin magnitudes to compare the measurability of spin magnitude vs. in-plane spin direction. We find that the in-plane spin direction could be measurable at SNRs accessible by current generation detectors, with the distinguishability SNR of varying in-plane spins comparable to or lower than varying the in-plane spin magnitude. We then remove the mode-asymmetry content from the waveforms and find that, i) removing mode-asymmetry increases the SNR at which in-plane spin direction can be measured and ii) not modelling mode-asymmetry will lead to measurement biases. The SNRs that we see at which the in-plane spins would be measurable and at which mode-asymmetric content impacts the measurements are the SNRs at which precession would be measurable, and we therefore conclude that modelling in-plane spin direction and mode-asymmetry effects is necessary for unbiassed measurements of precession.
Enabling gravitational-wave astronomy with spin-precessing black holes on generic orbits
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；Nottingham Centre of Gravity & School of Mathematical Sciences, University of Nottingham（诺丁汉大学重力中心与数学科学学院）；Department of Physics, University of Maryland（马里兰大学物理系）；Cornell Center for Astrophysics and Planetary Science, Cornell University（康奈尔大学天体物理学与行星科学中心）；Departament de Física, Universitat de les Illes Balears（巴利阿里群岛大学物理系）
Biased parameter inference of eccentric, spin-precessing binary black holes
Cardiff University（卡迪夫大学）；Indian Institute of Technology Madras（马德拉斯印度理工学院）；Penn State University（宾夕法尼亚州立大学）；Tata Institute of Fundamental Research（塔塔基础研究所）
Universal phenomenological relations between spherical harmonic modes in non-precessing eccentric binary black hole merger waveforms
Kavli Institute for Theoretical Physics, University of California Santa Barbara（加州大学圣塔芭芭拉分校卡弗里理论物理研究所）；Theoretical AstroPhysics Including Relativity and Cosmology, California Institute of Technology（加州理工学院理论天体物理学（含相对论与宇宙学）部门）；Department of Physics, University of California at Santa Barbara（加州大学圣塔芭芭拉分校物理系）；International Centre for Theoretical Sciences, Tata Institute of Fundamental Research（印度塔塔基础研究院国际理论科学中心）
Simulations of black-hole binaries with unequal masses or non-precessing spins: accuracy, physical properties, and comparison with post-Newtonian results
The High-Mass-Ratio Challenge in Gravitational Waveform Modelling
School of Physics and Astronomy, Cardiff University（卡迪夫大学物理与天文学院）；Mathematical Sciences & STAG Research Centre, University of Southampton（南安普顿大学数学科学与STAG研究中心）
SEOBNRv5PHM: Next generation of accurate and efficient multipolar precessing-spin effective-one-body waveforms for binary black holes
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；University of Maryland（马里兰大学）；Perimeter Institute for Theoretical Physics（理论物理前沿研究所）
Analysis of GWTC-3 with fully precessing numerical relativity surrogate models
University of Massachusetts, Dartmouth（达特茅斯马萨诸塞大学）；The University of Auckland（奥克兰大学）；OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery（引力波发现ARC卓越中心）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Nevada Center for Astrophysics（内华达天体物理学中心）；LIGO Laboratory, Massachusetts Institute of Technology（麻省理工学院LIGO实验室）；Massachusetts Institute of Technology（麻省理工学院）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理学研究所（爱因斯坦研究所））
GW190521 formation via three-body encounters in young massive star clusters
GW 190521是迄今为止观测到的最大质量的双黑洞合并，其主要成分位于对不稳定性（PI）质量隙中。在这里，我们通过年轻的大质量星团中的三体相遇研究了GW190521类系统的形成。我们进行了2次$\times10^5$模拟，模拟了BBH和大质量$\geq{60}\,$ M $_{\odot}$黑洞（BH）之间的二元-单元相互作用，包括$2.5$阶的后牛顿项和相对论踢的处方。在我们的初始条件下，我们考虑到通过恒星碰撞在PI质量间隙中形成BH的可能性。如果我们假设第一代黑洞具有低自旋，那么所有模拟的黑洞合并中的$\sim{0.17}\%$的分量质量、有效自旋和旋进自旋以及剩余质量和自旋都在$90\%$可信区间GW 190521之内。其中7个是第一代交换二进制，5个是第二代BBH。我们估计了年轻星团中通过双星-单星相互作用形成的类GW190521双星的合并率密度$\mathcal{R}_{\rm GW190521}\sim{0.03}\,$ Gpc $^{-3}\,$ yr $^{-1}$。这个速率对第一代BBH的自旋分布极其敏感。恒星碰撞、第二代合并和动力学交换是在年轻星团中产生类GW190521系统的关键因素。
The Cost of Circularity: Quantifying Eccentricity-Induced Biases in Binary Black Hole Inference
University of Wisconsin–Milwaukee（威斯康星大学密尔沃基分校）；The Pennsylvania State University（宾夕法尼亚州立大学）；University of California, Berkeley（加州大学伯克利分校）；University of Florida（佛罗里达大学）
Reexamining Evidence of a Pair-Instability Mass Gap in the Binary Black Hole Population
Northwestern University（西北大学）；NSF-Simons AI Institute for the Sky (SkAI)（NSF-西蒙斯天空人工智能研究所）；Department of Physics and Astronomy, Northwestern University（西北大学物理与天文学系）
Waveform systematics for binary neutron star gravitational wave signals: Effects of spin, precession, and the observation of electromagnetic counterparts
