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arXiv 1409.5601astro-ph.CO
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质量浓度关系与弱透镜峰计数

Mass - concentration relation and weak lensing peak counts

V. F. Cardone, S. Camera, M. Sereno, G. Covone, R. Maoli, R. Scaramella

摘要:

弱透镜收敛映象中的峰值统计是研究暗物质晕性质和约束宇宙学参数的有效工具。我们研究了可探测峰的数目及其与红移的比例如何依赖于团簇暗物质晕轮廓,并使用峰统计来约束质量-浓度(MC)关系的参数。我们调查的约束欧几里得任务可以设置MC系数也考虑到退化的宇宙学参数。为此,我们首先估计的峰的数量和红移分布不同的MC关系。我们发现,陡峭的质量依赖性和更大的归一化,更高的是可检测的集群的数量,与峰的总数变化高达$40\%$取决于MC关系。然后,我们执行的MC关系参数以及宇宙学参数的误差的Fisher矩阵预测。我们发现,Euclid检测到的峰数计数可以确定的归一化$A_v$,质量$B_v$和红移$C_v$斜率和固有的散射$σ_v$的MC关系到一个前所未有的精度为$σ(A_v)/A_v = 1\%$,$σ(B_v)/B_v = 4\%$,$σ(C_v)/C_v = 9\%$,$σ(σ_v)/σ_v = 1\%$,如果所有的宇宙学参数是已知的。如果我们放松这个严格的假设,约束条件就会降低,但是只设置一些参数或将峰值计数与普朗克数据相结合,就可以恢复非常好的结果。这种精确度可以让我们深入了解结构形成和演化的竞争场景,以及重子在集群组装中的作用。或者,对于固定的MC关系,当与普朗克结合时,未来的峰值计数可以与当前的BAO和SNeIa一样好地执行。

英文摘要:

The statistics of peaks in weak lensing convergence maps is a promising tool to investigate both the properties of dark matter haloes and constrain the cosmological parameters. We study how the number of detectable peaks and its scaling with redshift depend upon the cluster dark matter halo profiles and use peak statistics to constrain the parameters of the mass - concentration (MC) relation. We investigate which constraints the Euclid mission can set on the MC coefficients also taking into account degeneracies with the cosmological parameters. To this end, we first estimate the number of peaks and its redshift distribution for different MC relations. We find that the steeper the mass dependence and the larger the normalisation, the higher is the number of detectable clusters, with the total number of peaks changing up to $40\%$ depending on the MC relation. We then perform a Fisher matrix forecast of the errors on the MC relation parameters as well as cosmological parameters. We find that peak number counts detected by Euclid can determine the normalization $A_v$, the mass $B_v$ and redshift $C_v$ slopes and intrinsic scatter $σ_v$ of the MC relation to an unprecedented accuracy being $σ(A_v)/A_v = 1\%$, $σ(B_v)/B_v = 4\%$, $σ(C_v)/C_v = 9\%$, $σ(σ_v)/σ_v = 1\%$ if all cosmological parameters are assumed to be known. Should we relax this severe assumption, constraints are degraded, but remarkably good results can be restored setting only some of the parameters or combining peak counts with Planck data. This precision can give insight on competing scenarios of structure formation and evolution and on the role of baryons in cluster assembling. Alternatively, for a fixed MC relation, future peaks counts can perform as well as current BAO and SNeIa when combined with Planck.

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