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arXiv 1407.7548astro-ph.CO
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耦合暗能量模型的光线追迹模拟

Raytracing simulations of coupled dark energy models

Francesco Pace, Marco Baldi, Lauro Moscardini, David Bacon, Robert Crittenden

摘要:

暗物质和暗能量通常被认为只在引力作用下耦合。对这幅图的一个扩展是将暗能量建模为直接耦合到冷暗物质的标量场。这种耦合导致了新的物理效应,例如第五种力和依赖于时间的暗物质粒子质量。在这项工作中,我们研究的影响,耦合弱透镜统计,通过构建现实的模拟弱透镜地图,使用光线跟踪技术,通过N体宇宙学模拟。我们构建不同的透镜量的地图,覆盖范围从几角分到几度的尺度。的一致性$Λ$ CDM模型进行比较,不同的耦合暗能量模型,由指数标量场势(标准耦合暗能量的情况下)或由SUGRA潜在的(弹跳模型)。我们分析了几个统计量,我们的结果,在低红移的来源是在很大程度上与以前的工作CMB透镜由Carbone等人,2013.与$Λ$ CDM模型最显著的区别是由于扰动的增强增长和非线性动力学中的有效摩擦项。对于最极端的模型,我们看到功率谱的差异高达40%相比,$Λ$ CDM模型。线性物质过密度的不同时间演化可以解释大部分差异,但是当使用具有相同归一化的$Λ$ CDM模型对此进行控制时,由于暗物质粒子的运动方程中出现的摩擦项的影响,整体信号较小。

英文摘要:

Dark matter and dark energy are usually assumed to couple only gravitationally. An extension to this picture is to model dark energy as a scalar field coupled directly to cold dark matter. This coupling leads to new physical effects, such as a fifth-force and a time-dependent dark matter particle mass. In this work we examine the impact that coupling has on weak lensing statistics by constructing realistic simulated weak-lensing maps using raytracing techniques through N-body cosmological simulations. We construct maps for different lensing quantities, covering a range of scales from a few arcminutes to several degrees. The concordance $Λ$CDM model is compared to different coupled dark energy models, described either by an exponential scalar field potential (standard coupled dark energy scenario) or by a SUGRA potential (bouncing model). We analyse several statistical quantities and our results, with sources at low redshifts are largely consistent with previous work on CMB lensing by Carbone et al., 2013. The most significant differences from the $Λ$CDM model are due to the enhanced growth of the perturbations and to the effective friction term in non-linear dynamics. For the most extreme models, we see differences in the power spectra up to 40% compared to the $Λ$CDM model. The different time evolution of the linear matter overdensity can account for most of the differences, but when controlling for this using a $Λ$CDM model having the same normalization, the overall signal is smaller due to the effect of the friction term appearing in the equation of motion for dark matter particles.

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