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arXiv 2007.04968astro-ph.COastro-ph.GAgr-qc
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聚集暗能量在引力场宇宙学观测量上的印记

Clustering dark energy imprints on cosmological observables of the gravitational field

Farbod Hassani, Julian Adamek, Martin Kunz

AI总结:

本文使用N体代码“$k$-evolution”研究聚集暗能量对ISW-RS效应、弱引力透镜等引力场宇宙学观测量的影响,发现ISW-RS信号是约束暗能量聚集特性最具前景的探针。

摘要:

我们在聚集暗能量的背景下,研究了固定观测者过去光锥上的宇宙学观测量。我们重点关注直接探测引力场的观测量,即积分Sachs-Wolfe与非线性Rees-Sciama效应(ISW-RS)、弱引力透镜、引力红移和Shapiro时间延迟。借助我们专门构建的N体代码“$k$-evolution”(该代码能够追踪暗物质粒子与暗能量场的耦合演化),我们得以研究低声速$c_s$区域,在该区域暗能量扰动可能变得相当大。利用光线追踪,我们为每种效应生成了二维天图,并计算了它们的角功率谱。结果表明,ISW-RS信号是约束编码在$w-c_s^2$中的聚集暗能量特性最具前景的探针,因为当比较暗能量的两种不同声速时,暗能量的$\textit{线性}$聚集会使角功率谱在低$\ell$处改变约$30\\%$。弱引力透镜、Shapiro时间延迟和引力红移对聚集暗能量不够敏感,仅显示出百分之几的变化。在低$\ell$处,暗能量$\textit{非线性}$对所有功率谱的影响可以忽略不计,但在红移约为$0.85$观测时,在数百量级的多极矩处,收敛和ISW-RS角功率谱中的该影响分别达到约$2\\%$和$3\\%$。未来实现百分比精度测量的宇宙学巡天将允许以高置信度探测暗能量的聚集。

英文摘要:

We study cosmological observables on the past light cone of a fixed observer in the context of clustering dark energy. We focus on observables that probe the gravitational field directly, namely the integrated Sachs-Wolfe and non-linear Rees-Sciama effect (ISW-RS), weak gravitational lensing, gravitational redshift and Shapiro time delay. With our purpose-built $N$-body code "$k$-evolution" that tracks the coupled evolution of dark matter particles and the dark energy field, we are able to study the regime of low speed of sound $c_s$ where dark energy perturbations can become quite large. Using ray tracing we produce two-dimensional sky maps for each effect and we compute their angular power spectra. It turns out that the ISW-RS signal is the most promising probe to constrain clustering dark energy properties coded in $w-c_s^2$, as the $\textit{linear}$ clustering of dark energy would change the angular power spectrum by $\sim 30\%$ at low $\ell$ when comparing two different speeds of sound for dark energy. Weak gravitational lensing, Shapiro time-delay and gravitational redshift are less sensitive probes of clustering dark energy, showing variations of a few percent only. The effect of dark energy $\textit{non-linearities}$ in all the power spectra is negligible at low $\ell$, but reaches about $2\%$ and $3\%$, respectively, in the convergence and ISW-RS angular power spectra at multipoles of a few hundred when observed at redshift $\sim 0.85$. Future cosmological surveys achieving percent precision measurements will allow to probe the clustering of dark energy to a high degree of confidence.

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。

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