Measuring Eccentricity and Addressing Waveform Systematics in GW231123
Center for Gravitational Physics, The University of Texas at Austin（德克萨斯大学奥斯汀分校引力物理中心）；Center for Computational Relativity and Gravitation, Rochester Institute of Technology（罗切斯特理工学院计算相对论与引力中心）
Aasim Jan, Sophia Nicolella, Deirdre Shoemaker, Richard O'Shaughnessy
The gravitational-wave event GW231123_135430 is the heaviest binary black hole system observed by the LIGO--Virgo--KAGRA Collaboration to date, with the initial analysis indicating the individual black hole masses lie within or above the theorized pair-instability mass gap of roughly $60$--$130\,M_\odot$. The inference further suggests that both black holes possess high spins, measured to be $0.90^{+0.10}_{-0.19}$ and $0.80^{+0.20}_{-0.51}$. Therefore, the observation of this event suggests the formation of black holes from channels beyond the standard stellar collapse. However, different waveform models yield significantly different parameter estimates, possibly due to missing physics in the models used in inference. In this work, we carry out a reanalysis of GW231123 using a physically complete model, accounting for both spin precession and eccentricity. Our analysis shows that this event does not exhibit strong evidence for eccentricity and the exclusion of eccentricity has minimal impact on inference. Furthermore, for GW231123-like systems, even eccentricities as large as $0.15$ at $10$ Hz do not yield a confident nonzero eccentricity measurement. Through a zero-noise injection recovery study, we show that the observed discrepancies in the parameter estimates can be explained by disagreement in the waveform models at strong spin precession, with the degree of parameter bias in the zero-noise runs being comparable to that observed for the real signal. We also show that inference performed with an eccentric, aligned-spin waveform model can yield a confident nonzero eccentricity measurement due to the degeneracy between eccentricity and spin precession. Bayesian model selection, however, rules out this interpretation in favor of the eccentric, spin precessing hypothesis, which supports zero eccentricity -- a conclusion we confirm with additional zero-noise injection-recovery tests.
Post-Newtonian theory-inspired framework for characterizing eccentricity in gravitational 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））；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（塔塔基础研究院国际理论科学中心）
Large-Eccentricity Asymptotics and Fast Analytic Approximation for Fourier modes of Post-Newtonian Eccentric Waveforms
Instituto de Física Téorica UAM-CSIC, Universidad Autónoma de Madrid（马德里自治大学理论物理研究所）；Beijing Normal University（北京师范大学）；Hangzhou Institute for Advanced Study, UCAS（中国科学院大学杭州高等研究院）
Adding eccentricity to quasicircular binary-black-hole waveform models
从合并偏心双星黑洞的引力波信号的检测将产生前所未有的信息，在特定的情况下，如致密的星团和三体相互作用的动力学形成的致密双星的形成和演化。地面干涉仪LIGO和Virgo的引力波搜索依赖于准圆轨道上双星的分析波形模型。偏心合并的波形模型发展较少，只有少数的偏心合并的数值模拟是公开的，但几个偏心inspiral模型已经开发出后牛顿膨胀。在这里，我们提出了一种新的方法来转换的主导四极模式的任何圆形的分析双黑洞模型到偏心模型。首先，使用数值模拟，我们研究的额外的振幅和频率调制的偏心信号，不存在于他们的圆形同行。随后，我们确定了这些调制的合适的分析描述，并从指定为我们的训练数据集的12个数值模拟中插入关键参数。这使我们能够重建质量比为3和偏心率为0.2的任何波形的调制幅度和相位。我们发现，新模型与数值模拟的最小重叠约为0.98，在我们所有的测试数据集上，这些数据集以35 Hz的频率从aLIGO A+设计灵敏度开始缩放到50 M $_\odot$黑洞二进制。一个Python包\pyrex可以很容易地执行这种方法的计算。
Revisiting the Coprecessing Frame in the Presence of Orbital Eccentricity
California Institute of Technology（加州理工学院）；LIGO Laboratory, California Institute of Technology（LIGO实验室，加州理工学院）；Department of Physics & Astronomy, Amherst College（阿默斯特学院物理与天文系）；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）
Effective-one-body waveforms for extreme-mass-ratio binaries: Consistency with second-order gravitational self-force quasicircular results and extension to nonprecessing spins and eccentricity
Parameter estimation for the GWTC-4.0 catalog with phenomenological waveform models that include orbital eccentricity and an updated description of spin precession
Universitat de les Illes Balears（巴利阿里群岛大学）；Institut de Ciències de l’Espai (ICE, CSIC)（空间科学研究所）
Testing the nature of GW200105 by probing the frequency evolution of eccentricity
Inter-University Centre for Astronomy and Astrophysics（大学天文与天体物理中心）；Department of Physics, Vivekananda Satavarshiki Mahavidyalaya (affiliated to Vidyasagar University)（维韦卡南达萨塔瓦尔希基学院物理系（隶属维迪亚萨加尔大学））
Eccentric and unbound compact binaries in the LIGO-Virgo-KAGRA catalog: parameter estimation and waveform systematics with SEOBNRv6EHM
University of Nottingham（诺丁汉大学）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（阿尔伯特·爱因斯坦研究所））；University of Maryland（马里兰大学）
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）
Toward a complete understanding of the properties of GW190521
The University of Texas at Austin（德克萨斯大学奥斯汀分校）；California Institute of Technology（加州理工学院）；LIGO Laboratory（LIGO实验室）；Rochester Institute of Technology（罗切斯特理工学院）
