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arXiv 1708.00697astro-ph.CO
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结合CMB的Sunyaev-Zeldovich热簇数和功率谱的约束

Constraints from thermal Sunyaev-Zeldovich cluster counts and power spectrum combined with CMB

Laura Salvati, Marian Douspis, Nabila Aghanim

摘要:

热Sunyaev-Zel'dovich效应是近年来宇宙学和大尺度结构研究的热点之一。我们更新约束的宇宙学参数从星系团观测到的普朗克卫星在第一次尝试结合集群数计数和热气体的功率谱,使用新的值的光学深度,并采样在同一时间的宇宙学和标度关系参数。我们发现,在$Λ$ CDM模型中,tSZ功率谱的添加仅提供了仅相对于数目计数的小的改进,导致$68\%$ c.l.约束$Ω_m = 0.32 \pm 0.02$、$σ_8 = 0.77\pm0.03 $和$σ_8 (Ω_m/0.3)^{1/3}= 0.78\pm0.03$,并将与CMB原发性各向异性结果的差异(使用$τ$的新值更新)降低至$σ_8$上的$\simeq 1.6\, σ$。我们分析了标准模型的扩展,考虑了大质量中微子的影响,并改变了暗能量的状态方程参数。在第一种情况下,我们发现,增加的tSZ功率谱有助于在强烈改善宇宙学的限制,相对于计数的结果,导致$95\%$上限$\sum m_ν< 1.53 \, \text{eV}$。对于变化的暗能量EoS场景,当添加tSZ功率谱时,我们再次发现没有重要的改进,但是tSZ探针的组合仍然能够提供约束,产生$w = -1.0\pm 0.2$。在所有宇宙学场景中,调和CMB和tSZ探针的质量偏差仍然很低:与弱透镜和X射线质量估计比较或数值模拟的估计相比,$(1-b)\lesssim 0.66$。

英文摘要:

Thermal Sunyaev-Zel'dovich effect is one of the recent probes of cosmology and large scale structures. We update constraints on cosmological parameters from galaxy clusters observed by the Planck satellite in a first attempt to combine cluster number counts and power spectrum of hot gas, using the new value of the optical depth, and sampling at the same time on cosmological and scaling-relation parameters. We find that in the $Λ$CDM model, the addition of tSZ power spectrum provides only small improvements with respect to number counts only, leading to the $68\%$ c.l. constraints $Ω_m = 0.32 \pm 0.02$, $σ_8 = 0.77\pm0.03 $ and $σ_8 (Ω_m/0.3)^{1/3}= 0.78\pm0.03$ and lowering the discrepancy with CMB primary anisotropies results (updated with the new value of $τ$) to $\simeq 1.6\, σ$ on $σ_8$. We analyse extensions to standard model, considering the effect of massive neutrinos and varying the equation of state parameter for dark energy. In the first case, we find that the addition of tSZ power spectrum helps in strongly improving cosmological constraints with respect to number counts only results, leading to the $95\%$ upper limit $\sum m_ν< 1.53 \, \text{eV}$. For the varying dark energy EoS scenario, we find again no important improvements when adding tSZ power spectrum, but still the combination of tSZ probes is able in providing constraints, producing $w = -1.0\pm 0.2$. In all cosmological scenari the mass bias to reconcile CMB and tSZ probes remains low: $(1-b)\lesssim 0.66$ as compared to estimates from weak lensing and Xray mass estimate comparisons or numerical simulations.

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