Planck 2015 results XIV. Dark energy and modified gravity
Planck 2015 results XIV. Dark energy and modified gravity
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DOI：
10.1051/0004-6361/201525814
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发表时间：
2016-10-01
影响因子：
6.5
通讯作者：
Zonca, A.
中科院分区：
文献类型：
--
作者：
Ade, P. A. R.;Aghanim, N.;Zonca, A.
我们研究了普朗克数据的暗能量（DE）和修改后的重力（MG）超出标准的宇宙学常数的情况下的模型的影响。我们从DE只直接影响背景演化的情况开始，考虑状态方程w（a）的泰勒展开，以及与最小耦合DE标量场的势相关的主成分分析和参数化。当在早期估计DE的密度时，我们显着改进了现有的约束，并发现它必须低于临界密度的2%（95%置信度），即使被迫仅在z < 50时发挥作用。然后，我们转移到一般参数化的DE或MG微扰，包括有效场理论和现象学的引力势在MG模型。最后，我们测试了一系列特定的模型，如k-本质，f（R）理论和耦合DE。除了最新的普朗克数据，我们的主要分析，我们使用的背景约束重子声振荡，Ia型超新星，和当地测量的哈勃常数。我们进一步显示的宇宙学扰动，如红移空间扭曲和弱引力透镜的测量的影响。这些额外的探针是测试MG模型和打破普朗克和背景数据集的组合中仍然存在的简并性的重要工具。所有的结果，只包括背景参数化（扩展的状态方程，早期DE，一般潜力在最小耦合标量场或主成分分析）与ACDM协议。当测试也改变扰动的模型时（即使背景固定为ACDM），在一些情况下会出现一些张力：当用选定的时间依赖性参数化与引力势相关的观测值时，普朗克TT + lowP的最大张力类似于2 sigma;当包括外部数据集时，张力最多增加到3 sigma。然而，当包括CMB透镜时，它消失。
We study the implications of Planck data for models of dark energy (DE) and modified gravity (MG) beyond the standard cosmological constant scenario. We start with cases where the DE only directly affects the background evolution, considering Taylor expansions of the equation of state w(a), as well as principal component analysis and parameterizations related to the potential of a minimally coupled DE scalar field. When estimating the density of DE at early times, we significantly improve present constraints and find that it has to be below similar to 2% (at 95% confidence) of the critical density, even when forced to play a role for z < 50 only. We then move to general parameterizations of the DE or MG perturbations that encompass both effective field theories and the phenomenology of gravitational potentials in MG models. Lastly, we test a range of specific models, such as k-essence, f(R) theories, and coupled DE. In addition to the latest Planck data, for our main analyses, we use background constraints from baryonic acoustic oscillations, type-Ia supernovae, and local measurements of the Hubble constant. We further show the impact of measurements of the cosmological perturbations, such as redshift-space distortions and weak gravitational lensing. These additional probes are important tools for testing MG models and for breaking degeneracies that are still present in the combination of Planck and background data sets. All results that include only background parameterizations (expansion of the equation of state, early DE, general potentials in minimally-coupled scalar fields or principal component analysis) are in agreement with ACDM. When testing models that also change perturbations (even when the background is fixed to ACDM), some tensions appear in a few scenarios: the maximum one found is similar to 2 sigma for Planck TT + lowP when parameterizing observables related to the gravitational potentials with a chosen time dependence; the tension increases to, at most, 3 sigma when external data sets are included. It however disappears when including CMB lensing.