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arXiv 2103.14663gr-qcastro-ph.COastro-ph.SR
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黑暗中的宇宙学:论源粒子数模型对引力波宇宙学的重要性

Cosmology in the dark: On the importance of source population models for gravitational-wave cosmology

S. Mastrogiovanni, K. Leyde, C. Karathanasis, E. Chassande-Mottin, D. A. Steer, J. Gair, A. Ghosh, R. Gray, S. Mukherjee, S. Rinaldi

摘要:

关于致密天体的质量谱形状的知识可以用来帮助打破引力波(GW)源的质量和红移之间的简并性,从而可以用来在没有从电磁观测获得的红移测量的情况下推断宇宙学参数。在本文中,我们广泛研究了这种方法的不同方面,包括其计算限制和可实现的精度。我们专注于地面探测器与当前和未来的灵敏度,我们首先进行分析的一组广泛的模拟数据与层次贝叶斯方案推断人口和宇宙学参数。我们考虑一个总体模型(幂律加高斯),它表现出特征尺度(质谱的极端、聚集点的存在),可以间接估计源红移。我们对这个星表的分析强调并量化了源种群和宇宙学参数之间的紧密相互作用,以及初始假设(无论是对源还是宇宙学参数制定的)的影响。然后,我们验证了我们的研究结果的“端到端”的分析,使用模拟GW数据和后验样本生成的贝叶斯采样器用于GW参数估计,从而反映了分析链用于观测数据的第一次在文献中。然后,我们的研究结果使我们重新检查的估计$H_0$获得GWTC-1,我们明确地显示人口假设如何影响最终的$H_0$结果。我们的研究结果强调了人口和宇宙学参数联合推断的重要性(而不是分开,因为通常假设)。唯一的例外,正如我们所讨论的,是如果电磁对应物被观察到所有的BBH事件:那么人口假设对宇宙学参数的估计影响较小。

英文摘要:

Knowledge of the shape of the mass spectrum of compact objects can be used to help break the degeneracy between the mass and redshift of the gravitational wave (GW) sources, and thus can be used to infer cosmological parameters in the absence of redshift measurements obtained from electromagnetic observations. In this paper, we study extensively different aspects of this approach, including its computational limits and achievable accuracy. We focus on ground-based detectors with current and future sensitivities, we first perform the analysis of an extensive set of simulated data with a hierarchical Bayesian scheme inferring population and cosmological parameters. We consider a population model (power-law plus Gaussian) which exhibits characteristic scales (extremes of the mass spectrum, presence of an accumulation point) that allows an indirect estimate of the source redshift. Our analysis of this catalog highlights and quantifies the tight interplay between source population and cosmological parameters, as well as the influence of initial assumptions (whether formulated on the source or cosmological parameters). We then validate our results by an "end-to-end" analysis using simulated GW data and posterior samples generated from Bayesian samplers used for GW parameter estimation, thus mirroring the analysis chain used for observational data for the first time in literature. Our results then lead us to re-examine the estimation of $H_0$ obtained with GWTC-1, and we show explicitly how population assumptions impact the final $H_0$ result. Our results underline the importance of inferring population and cosmological parameters jointly (and not separately as is often assumed). The only exception, as we discuss, is if an electromagnetic counterpart was to be observed for all the BBH events: then the population assumptions have less impact on the estimation of cosmological parameters.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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