arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1111.1556astro-ph.CO
收藏

振荡暗能量宇宙学中的结构形成

Structure formation in cosmologies with oscillating dark energy

F. Pace, C. Fedeli, L. Moscardini, M. Bartelmann

摘要:

我们研究了以振荡状态方程为特征的动力学暗能量模型对宇宙结构形成和演化的影响。暗能量的状态方程参数w(z)的红移演化由两个参数表征,描述振荡的振幅和频率。我们考虑六种不同的振荡暗能量模型,每个模型的特征在于一组不同的参数值。在暗能量在感兴趣的尺度上不聚集的共同假设下,我们研究了宇宙结构形成的不同方面。特别是,我们自洽地解决了球形塌陷问题。然后,我们估计几个宇宙学观测的行为,如线性增长因子,集成的萨克斯-沃尔夫(ISW)效应,质量结构的数量计数,以及物质和宇宙剪切功率谱。我们表明,独立的振幅和频率的暗能量振荡,没有上述观测值显示的振荡行为作为红移的函数。这是因为所述观测量是宇宙历史上膨胀率的某些函数的积分。我们还注意到,相对于基准LambdaCDM宇宙学的期望值的偏差通常很小,并且在大多数情况下,区分振荡的暗能量模型将是困难的。宇宙剪切功率谱和星系团丰度提供了对这一结论的支持,对于某些模型,宇宙剪切功率谱在很宽的角标度范围内显示出\sim 10%的差异,而星系团丰度在$\sim 10-20%$水平上被修改为$z \gtrsim 0.6$,以便将来进行广泛的弱透镜巡天。

英文摘要:

{abridged} We study the imprints on the formation and evolution of cosmic structures of dynamical dark energy models, characterized by an oscillating equation of state. The redshift evolution of the equation of state parameter w(z) for dark energy is characterized by two parameters, describing the amplitude and the frequency of the oscillations. We consider six different oscillating dark energy models, each characterized by a different set of parameter values. Under the common assumption that dark energy is not clustering on the scales of interest, we study different aspects of cosmic structure formation. In particular, we self-consistently solve the spherical collapse problem. We then estimate the behavior of several cosmological observables, such as the linear growth factor, the Integrated Sachs-Wolfe (ISW) effect, the number counts of massive structures, and the matter and cosmic shear power spectra. We show that, independently of the amplitude and the frequency of the dark energy oscillations, none of the aforementioned observables show an oscillating behavior as a function of redshift. This is a consequence of the said observables' being integrals over some functions of the expansion rate over cosmic history. We also notice that deviations with respect to the expectations for a fiducial LambdaCDM cosmology are generically small, and in the majority of the cases distinguishing an oscillating dark energy model would be difficult. Exceptions to this conclusion are provided by the cosmic shear power spectrum, which for some of the models shows a difference at the level of \sim 10% over a wide range of angular scales, and the abundance of galaxy clusters, which is modified at the $\sim 10-20%$ level at $z \gtrsim 0.6$ for future wide weak lensing surveys.

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。

↑