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arXiv 2103.03283astro-ph.CO
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星系团稀疏度、气体质量分数和重子声学振荡的宇宙学约束

Cosmological Constraints from Galaxy Cluster Sparsity, Cluster Gas Mass Fraction and Baryon Acoustic Oscillations Data

P. S. Corasaniti, M. Sereno, S. Ettori

摘要:

近年来,大量完整的星系团样本的可用性使得许多宇宙学参数推断分析使用星系团数计数。这些提供了对宇宙物质密度$Ω_m$和物质密度波动幅度$σ_8$的限制,可替代从其他标准探测器获得的限制。然而,系统学的不确定性,如质量校准偏差和选择效应,仍然可能显着影响这些数据分析。因此,这是及时探索其他代理的星系团宇宙学,可以提供宇宙学的限制,补充那些从集群数量计数。在这里,我们使用测量的集群稀疏性从弱透镜质量估计的LC $^2$ -{ \it单}和HSC-XXL集群目录,以推断一个平坦的$Λ$ CDM模型的约束。聚类稀疏性具有对选择和质量校准偏差不敏感的优点。另一方面,它主要约束$Ω_m$和$σ_8$的简并组合(沿着$S_8=σ_8\sqrt{Ω_m/0.3}$的近似恒定曲线),并且在较小程度上约束约化的哈勃参数$h$。因此,为了打破内部参数退化,我们进行了组合的可能性分析的集群稀疏与集群气体质量分数测量和BAO数据。我们发现边缘的限制,是竞争与那些从其他标准的宇宙探测器:$Ω_m=0.316\pm 0.013$,$σ_8=0.757\pm 0.067$(对应于$S_8=0.776\pm 0.064$)和$h=0.696\pm 0.017$在$1σ$。此外,假设一个保守的高斯先验的气体质量分数数据的质量偏差,我们发现一个下限的气体损耗因子$Y_{b,500c}\gtrsim 0.89$。

英文摘要:

In recent years, the availability of large, complete cluster samples has enabled numerous cosmological parameter inference analyses using cluster number counts. These have provided constraints on the cosmic matter density $Ω_m$ and the amplitude of matter density fluctuations $σ_8$ alternative to those obtained from other standard probes. However, systematics uncertainties, such as the mass calibration bias and selection effects, may still significantly affect these data analyses. Hence, it is timely to explore other proxies of galaxy cluster cosmology that can provide cosmological constraints complementary to those obtained from cluster number counts. Here, we use measurements of the cluster sparsity from weak lensing mass estimates of the LC$^2$-{\it single} and HSC-XXL cluster catalogs to infer constraints on a flat $Λ$CDM model. The cluster sparsity has the advantage of being insensitive to selection and mass calibration bias. On the other hand, it primarily constrains a degenerate combination of $Ω_m$ and $σ_8$ (along approximately constant curves of $S_8=σ_8\sqrt{Ω_m/0.3}$), and to less extent the reduced Hubble parameter $h$. Hence, in order to break the internal parameter degeneracies we perform a combined likelihood analysis of cluster sparsities with cluster gas mass fraction measurements and BAO data. We find marginal constraints that are competitive with those from other standard cosmic probes: $Ω_m=0.316\pm 0.013$, $σ_8=0.757\pm 0.067$ (corresponding to $S_8=0.776\pm 0.064$) and $h=0.696\pm 0.017$ at $1σ$. Moreover, assuming a conservative Gaussian prior on the mass bias of gas mass fraction data, we find a lower limit on the gas depletion factor $Y_{b,500c}\gtrsim 0.89$.

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