arXiv 2302.050102023-02-10astro-ph.CO

基于CSST星系团的暗能量约束

Constraints on dark energy from the CSST galaxy clusters

Yufei Zhang, Mingjing Chen, Zhonglue Wen, Wenjuan Fang

备注：: 19 pages, 5 figures, 4 tables. Accepted for publication in Research in Astronomy and Astrophysics
发表信息：: Res. Astron. Astrophys. 23 045011 (2023)
DOI：: 10.1088/1674-4527/acc155

AI总结：

本研究评估了CSST星系团样本约束暗能量的潜力，通过构建Fisher矩阵预测了在自校准和已知标度关系方案下对 $w_0$CDM 和 $w_0w_a$CDM 模型参数的约束，发现扩展红移范围可显著提升优值，且红移误差影响可忽略但需严格控制质量偏差。

摘要：

我们研究了China Space Station Telescope (CSST) 巡天预期获得的星系团样本在约束暗能量性质方面的潜力。通过将给定真实质量下观测星系团质量的分布建模为对数正态分布，并在观测质量上采用选择阈值 $M_{200m} \geq 0.836 \times 10^{14} h^{-1}M_{\odot}$，我们发现CSST可以探测到红移范围 $0 \leq z \leq 1.5$ 内约 $4.1 \times 10^{5}$ 个星系团。我们构建了CSST星系团数计数的Fisher矩阵，并预测了具有常数 ($w_0$CDM) 和时间依赖 ($w_0w_a$CDM) 状态方程模型的暗能量参数约束。在自校准方案中，$w_0$CDM 模型的暗能量状态方程参数 $w_0$ 可被约束至 $Δw_0 = 0.036$。若将 $w_a$ 作为自由参数加入，对于 $w_0w_a$CDM 模型，我们得到 $Δw_0 = 0.077$ 和 $Δw_a = 0.39$，且 ($w_0,w_a$) 的优值 (Figure of Merit) 为 68.99。如果我们对可观测质量-质量标度关系有完美的认知（“known SR”方案），对于 $w_0$CDM 模型我们将得到 $Δw_0 = 0.012$，对于 $w_0w_a$CDM 模型得到 $Δw_0 = 0.062$ 和 $Δw_a = 0.24$。($w_0,w_a$) 的暗能量优值增加至 343.25。通过将星系团的最大红移从 $z_{max} \sim 1.5$ 扩展到 $z_{max} \sim 2$，($w_0,w_a$) 的暗能量优值增加至 89.72（自校准方案）和 610.97（“known SR”方案），分别提升了约 $1.30$ 倍和 $1.78$ 倍。我们发现，只要星系团的红移误差小于 0.01（CSST 可实现），星系团红移不确定性对暗能量约束的影响就可忽略不计。我们还发现，对数质量的偏差必须校准至 $0.30$ 或更好，以避免显著的暗能量参数偏差。

英文摘要：

We study the potential of the galaxy cluster sample expected from the China Space Station Telescope (CSST) survey to constrain dark energy properties. By modelling the distribution of observed cluster mass for a given true mass to be log-normal and adopting a selection threshold in the observed mass $M_{200m} \geq 0.836 \times 10^{14} h^{-1}M_{\odot}$, we find about $4.1 \times 10^{5}$ clusters in the redshift range $0 \leq z \leq 1.5$ can be detected by the CSST. We construct the Fisher matrix for the cluster number counts from CSST, and forecast constraints on dark energy parameters for models with constant ($w_0$CDM) and time dependent ($w_0w_a$CDM) equation of state. In the self-calibration scheme, the dark energy equation of state parameter $w_0$ of $w_0$CDM model can be constrained to $Δw_0 = 0.036$. If $w_a$ is added as a free parameter, we obtain $Δw_0 = 0.077$ and $Δw_a = 0.39$ for the $w_0w_a$CDM model, with a Figure of Merit for ($w_0,w_a$) to be 68.99. Should we had perfect knowledge of the observable-mass scaling relation (``known SR" scheme), we would obtain $Δw_0 = 0.012$ for $w_0$CDM model, $Δw_0 = 0.062$ and $Δw_a = 0.24$ for $w_0w_a$CDM model. The dark energy Figure of Merit of ($w_0,w_a$) increases to 343.25. By extending the maximum redshift of the clusters from $z_{max} \sim 1.5$ to $z_{max} \sim 2$, the dark energy Figure of Merit for ($w_0,w_a$) increases to 89.72 (self-calibration scheme) and 610.97 (``known SR" scheme), improved by a factor of $\sim 1.30$ and $\sim 1.78$, respectively. We find that the impact of clusters' redshift uncertainty on the dark energy constraints is negligible as long as the redshift error of clusters is smaller than 0.01, achievable by CSST. We also find that the bias in logarithm mass must be calibrated to be $0.30$ or better to avoid significant dark energy parameter bias.

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摘要：

英文摘要：

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