Spin it as you like: The (lack of a) measurement of the spin tilt distribution with LIGO-Virgo-KAGRA binary black holes
Spin it as you like: The (lack of a) measurement of the spin tilt distribution with LIGO-Virgo-KAGRA binary black holes
复制标题
随心所欲地旋转：LIGO-Virgo-KAGRA 双黑洞自旋倾斜分布的（缺乏）测量
DOI：
10.1051/0004-6361/202245084
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发表时间：
2022
影响因子：
6.5
通讯作者：
Talbot, Colm
中科院分区：
文献类型：
--
作者：
Vitale, Salvatore;Biscoveanu, Sylvia;Talbot, Colm
背景越来越多的引力波源被用来测量致密天体、黑洞和中子星等潜在天体物理群体的特性。大多数检测到的系统都是黑洞双星系统。虽然通过分析最新的 LIGO-Virgo-KAGRA (LVK) 目录 GWTC-3，我们对黑洞有了很多了解，但对黑洞自旋方向的天体物理分布的测量仍然难以捉摸。通常通过测量每个黑洞自旋和轨道角动量之间的倾斜角 (cosτ) 的余弦来探测这一点，其中 cosτ= +1 是完美对齐的。目标LVK 协作组将 cosτ 分布建模为各向同性分量和高斯分量的混合，平均值固定为 +1，宽度根据数据测量。我们想要验证数据是否需要在 cosτ= +1 处存在这样的峰值。方法我们使用了天体物理倾斜分布的各种替代模型，并使用 LVK GWTC-3 目录测量了它们的参数。结果我们发现（a）增强 LVK 模型，使得高斯的平均值 μ 不固定在 +1，返回的结果强烈依赖于先验。如果我们允许 μ> +1，那么所得到的天体物理 cosτ 分布在 +1 处达到峰值，并且看起来是线性的，而不是高斯分布。如果我们约束−1 ≤μ≤ +1，高斯分量在（中值和90%对称可信区间）处达到峰值。另外两个双组分混合物模型产生的 cosτ 分布要么具有以 [ − 0.5, +1] 为中心的宽峰，要么具有跨越范围 [ − 0.5, +1] 的平台，在 +1 处没有清晰的峰。 (b) 我们考虑的所有模型都同意在 -1 左右不存在过量的黑洞倾斜。 (c) 虽然产生完全不同的后验，但本工作中考虑的模型具有在误差条内相同的贝叶斯证据。结论我们得出的结论是，当前数据集的信息不足以得出关于自旋倾斜的天体物理分布的任何独立于模型的结论，除了没有多余的具有负对齐倾斜的自旋。
ContextThe growing set of gravitational-wave sources is being used to measure the properties of the underlying astrophysical populations of compact objects, black holes, and neutron stars. Most of the detected systems are black hole binaries. While much has been learned about black holes by analyzing the latest LIGO-Virgo-KAGRA (LVK) catalog, GWTC-3, a measurement of the astrophysical distribution of the black hole spin orientations remains elusive. This is usually probed by measuring the cosine of the tilt angle (cosτ) between each black hole spin and the orbital angular momentum, with cosτ= +1 being perfect alignment.AimsThe LVK Collaboration has modeled the cosτdistribution as a mixture of an isotropic component and a Gaussian component with mean fixed at +1 and width measured from the data. We want to verify if the data require the existence of such a peak at cosτ= +1.MethodsWe used various alternative models for the astrophysical tilt distribution and measured their parameters using the LVK GWTC-3 catalog.ResultsWe find that (a) augmenting the LVK model, such that the meanμof the Gaussian is not fixed at +1, returns results that strongly depend on priors. If we allowμ> +1, then the resulting astrophysical cosτdistribution peaks at +1 and looks linear, rather than Gaussian. If we constrain −1 ≤μ≤ +1, the Gaussian component peaks at (median and 90% symmetric credible interval). Two other two-component mixture models yield cosτdistributions that either have a broad peak centered at or a plateau that spans the range [ − 0.5, +1], without a clear peak at +1. (b) All of the models we considered agree as to there being no excess of black hole tilts at around −1. (c) While yielding quite different posteriors, the models considered in this work have Bayesian evidences that are the same within error bars.ConclusionsWe conclude that the current dataset is not sufficiently informative to draw any model-independent conclusions on the astrophysical distribution of spin tilts, except that there is no excess of spins with negatively aligned tilts.