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arXiv 1202.0640astro-ph.CO
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星系团的关联函数与重子声学振荡的探测

The correlation function of galaxy clusters and detection of baryon acoustic oscillations

T. Hong, J. L. Han, Z. L. Wen, L. Sun, H. Zhan

摘要:

我们计算了从文、汉、刘三家星系团星表中选出的13,904个z \leq 0.4的星系团的关联函数。在10 h ^(-1)Mpc \leq r \leq 50 h ^(-1)Mpc的尺度上,关联函数可用幂律模型拟合,对于丰度为R \geq 15的簇,相关长度较大,为R_0=18.84 \pm 0.27 h^(-1)Mpc,相关长度较小,为R_0=16.15 \pm 0.13 h^(-1)具有R \geq 5丰富度的簇的Mpc。幂律指数γ=2.1对于所有聚类子样本几乎是相同的。在r ~ 110 h^(-1)Mpc处探测到一个显著的重子声学振荡(BAO)峰,其显著性为~ 1.9σ。通过分析20 h^(-1)Mpc \leq r \leq 200 h^(-1)Mpc范围内的关联函数,发现距离参数的约束条件为D_v(0.276)=1077 \pm 55(1σ)Mpc和h=0.73 \pm 0.039(1σ),这与WMAP的7年宇宙学一致.然而,来自星团样品的BAO信号比预期的要强,导致相当低的物质密度Ω_mh^2 =0.093 \pm 0.0077(1σ),这与WMAP的7年结果偏离了3 σ以上。计算了GMBCG聚类样本的关联函数,证实了我们对BAO特征的检测。

英文摘要:

We calculate the correlation function of 13,904 galaxy clusters of z \leq 0.4 selected from the cluster catalog of Wen, Han & Liu. The correlation function can be fitted with a power-law model ξ(r)=(r/R_0)^γ on the scales of 10h^(-1)Mpc \leq r \leq 50h^(-1)Mpc, with a larger correlation length of R_0=18.84\pm0.27 h^(-1)Mpc for clusters with a richness of R \geq 15 and a smaller length of R_0=16.15 \pm 0.13 h^(-1)Mpc for clusters with a richness of R \geq 5. The power law index of γ=2.1 is found to be almost the same for all cluster subsamples. A pronounced baryon acoustic oscillations (BAO) peak is detected at r ~ 110 h^(-1)Mpc with a significance of ~ 1.9σ. By analyzing the correlation function in the range of 20 h^(-1)Mpc \leq r \leq 200 h^(-1)Mpc, we find the constraints on distance parameters are D_v(0.276)=1077\pm55(1σ) Mpc and h=0.73 \pm 0.039 (1σ), which are consistent with the WMAP 7-year cosmology. However, the BAO signal from the cluster sample is stronger than expected and leads to a rather low matter density Ω_m h^2=0.093\pm0.0077 (1σ), which deviates from the WMAP 7-year result by more than 3 σ. The correlation function of the GMBCG cluster sample is also calculated and our detection of the BAO feature is confirmed.

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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