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arXiv 1201.3568astro-ph.CO
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相互作用暗能量模型中的晕质量函数

The halo mass function in interacting Dark Energy models

Weiguang Cui, Marco Baldi, Stefano Borgani

摘要:

本文详细研究了暗能量(DE)和冷暗物质(CDM)粒子之间的直接相互作用对星系团和星系团晕质量函数(HMF)的影响。利用{ \small CoDECS}模拟的公共晕目录,我们基于FoF算法和SO晕识别,针对不同的过密度阈值$Δ_{c}$,推导了几种不同类型耦合DE场景的HMF.我们比较计算的HMF耦合DE宇宙学与$Λ$ CDM以及与标准的解析拟合函数的预测。我们的研究结果表明,标准拟合函数仍然合理地再现FoF和SO HMF的相互作用DE宇宙学在中等质量和低红移,一旦重新标度的特征振幅的线性密度扰动的每个特定的模型,如$σ_{8}$。然而,我们也发现,这种明显的简并与$σ_{8}$被打破的高质量的尾巴和红移演化的HMF,与偏差超过$\sim 10%$的大多数模型正在调查。此外,相对于标准拟合函数的预测与$σ_{8}$的特征值的差异显示-对于某些模型-一个强烈的依赖于用于晕识别的球形过密度阈值$Δ_{c}$。我们发现,这种效果是由于在这些模型中的低红移晕浓度显着增加,但在大多数的宇宙学场景中考虑这项工作是缺席。因此,我们可以得出结论,HMF的普适性是违反了宇宙学模型,具有DE和CDM之间的直接相互作用。

英文摘要:

We present a detailed investigation of the effects that a direct interaction between Dark Energy (DE) and Cold Dark Matter (CDM) particles imprints on the Halo Mass Function (HMF) of groups and clusters of galaxies. Making use of the public halo catalogs of the {\small CoDECS} simulations, we derive the HMF for several different types of coupled DE scenarios both based on the FoF algorithm and on the SO halo identification for different values of the overdensity threshold $Δ_{c}$. We compare the computed HMFs for coupled DE cosmologies with $Λ$CDM as well as with the predictions of the standard analytic fitting functions. Our results show that the standard fitting functions still reproduce reasonably well both the FoF and the SO HMFs of interacting DE cosmologies at intermediate masses and at low redshifts, once rescaled to the characteristic amplitude of linear density perturbations of each specific model as given by $σ_{8}$. However, we also find that such apparent degeneracy with $σ_{8}$ is broken both by the high-mass tail and by the redshift evolution of our HMFs, with deviations beyond $\sim 10%$ for most of the models under investigation. Furthermore, the discrepancy with respect to the predictions of standard fitting functions rescaled with the characteristic value of $σ_{8}$ shows -- for some models -- a strong dependence on the spherical overdensity threshold $Δ_{c}$ used for the halo identification. We find that such effect is due to a significant increase of halo concentration at low redshifts in these models, that is however absent in the majority of the cosmological scenarios considered in this work. We can therefore conclude that the universality of the HMF is violated by cosmological models that feature a direct interaction between DE and CDM.

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