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arXiv 1302.2364astro-ph.CO
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暗能量宇宙学中的星系团浓度-质量关系

The galaxy cluster concentration-mass relation in dark energy cosmologies

Cristiano De Boni

摘要:

我们利用数值模拟不同的暗能量宇宙学来研究星系团中的浓度-质量关系。特别是,我们考虑一个参考λ冷暗物质(LambdaCDM)模型,两个具有动态暗能量的模型,被视为一个精粹标量场[使用Ratra和Peebles(RP)和超重力(SUGRA)势形式],以及两个扩展的精粹模型,一个具有正耦合,一个具有负耦合(分别为EQp和EQn),其中精粹标量场与引力非最小地相互作用(标量张量理论)。所有的模型进行归一化,以匹配微波微波各向异性探针3(WMAP 3)的CMB数据。[摘要]我们既考虑了完整的集群和组的目录,也考虑了松弛对象的子样本。我们的参考LambdaCDM模型的c-M关系与文献中的结果符合得很好,并且弛豫对象相对于完整样本具有更高的归一化和更小的斜率。对于不同的暗能量模型,我们发现,对于LambdaCDM,RP和SUGRA的c-M关系的归一化与增长因子D+和功率谱归一化σ 8有关,具有较高σ 8 D+值的模型也具有较高的归一化。这个简单的方案不再适用于EQp和EQn,因为在这些模型中,它是一个依赖于时间的有效引力相互作用,其红移的演变取决于耦合的符号。这导致EQp(EQn)模型中预期归一化的降低(增加)。这一结果显示了重力与表征EQ模型的精髓标量场之间的耦合的直接表现,所述EQ模型在背景水平下不可见,但可以在非线性状态下进行研究。

英文摘要:

We use numerical simulations of different dark energy cosmologies to investigate the concentration-mass (c-M) relation in galaxy clusters. In particular, we consider a reference Lambda cold dark matter (LambdaCDM) model, two models with dynamical dark energy, viewed as a quintessence scalar field [using a Ratra and Peebles (RP) and a supergravity (SUGRA) potential form], and two extended quintessence models, one with positive and one with negative coupling (EQp and EQn respectively), where the quintessence scalar field interacts non-minimally with gravity (scalar-tensor theories). All the models are normalized in order to match CMB data from Wilkinson Microwave Anisotropy Probe 3 (WMAP3). [Abridged] We consider both the complete catalog of clusters and groups and a subsample of relaxed objects. The c-M relation of our reference LambdaCDM model is in good agreement with the results in literature, and relaxed objects have a higher normalization and a shallower slope with respect to the complete sample. For the different dark energy models, we find that for LambdaCDM, RP and SUGRA the normalization of the c-M relation is linked to the growth factor D+ and the power spectrum normalization sigma8, with models having a higher value of sigma8 D+ having also a higher normalization. This simple scheme is no longer valid for EQp and EQn because in these models it is present a time dependent effective gravitational interaction, whose redshift evolution depends on the sign of the coupling. This leads to a decrease (increase) of the expected normalization in the EQp (EQn) model. This result shows a direct manifestation of the coupling between gravity and the quintessence scalar field characterizing EQ models that cannot be seen at the background level but can be investigated in the non-linear regime.

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