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arXiv 1409.4540astro-ph.CO
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约束暗扇区扰动II:ISW和CMB透镜层析成像

Constraining dark sector perturbations II: ISW and CMB lensing tomography

Bjoern Soergel, Tommaso Giannantonio, Jochen Weller, Richard A. Battye

摘要:

任何偏离宇宙学常数的暗能量(DE)或修正引力(MG)模型都需要对其扰动进行一致的处理,这可以用有效熵扰动和各向异性应力来描述。我们已经考虑了最近提出的通用参数化DE/MG扰动,并将其数据从普朗克卫星和6个星系目录,包括温度星系(Tg),CMB透镜星系和星系星系(GG)的相关性。结合这些可观的结构形成与测试的背景扩展,使我们能够调查的DE/MG在背景和微扰水平的属性。我们对DE/MG的约束与宇宙学常数范式基本一致,同时我们也发现对状态方程w(假设为常数)的约束依赖于微扰演化的模型假设。我们得到$w=-0.92^{+0.20}_{-0.16}$(95%CL; CMB+gg+Tg)在熵扰动的情况下,在各向异性应力的情况下,结果是$w=-0.86^{+0.17}_{-0.16}$。包括透镜相关性使结果向更高的w值移动。如果我们在最近的重子声学振荡(BAO)测量的膨胀历史上包括一个先验,我们发现,在$w=-1$附近的约束收紧,使得它不可能测量任何DE/MG扰动演化参数。然而,如果即将到来的观测,如DES,欧几里得或LSST显示出偏离宇宙学常数的迹象,我们的形式主义将是一个有用的工具,对模型选择在黑暗的部门。

英文摘要:

Any Dark Energy (DE) or Modified Gravity (MG) model that deviates from a cosmological constant requires a consistent treatment of its perturbations, which can be described in terms of an effective entropy perturbation and an anisotropic stress. We have considered a recently proposed generic parameterisation of DE/MG perturbations and compared it to data from the Planck satellite and six galaxy catalogues, including temperature-galaxy (Tg), CMB lensing-galaxy and galaxy-galaxy (gg) correlations. Combining these observables of structure formation with tests of the background expansion allows us to investigate the properties of DE/MG both at the background and the perturbative level. Our constraints on DE/MG are mostly in agreement with the cosmological constant paradigm, while we also find that the constraint on the equation of state w (assumed to be constant) depends on the model assumed for the perturbation evolution. We obtain $w=-0.92^{+0.20}_{-0.16}$ (95% CL; CMB+gg+Tg) in the entropy perturbation scenario; in the anisotropic stress case the result is $w=-0.86^{+0.17}_{-0.16}$. Including the lensing correlations shifts the results towards higher values of w. If we include a prior on the expansion history from recent Baryon Acoustic Oscillations (BAO) measurements, we find that the constraints tighten closely around $w=-1$, making it impossible to measure any DE/MG perturbation evolution parameters. If, however, upcoming observations from surveys like DES, Euclid or LSST show indications for a deviation from a cosmological constant, our formalism will be a useful tool towards model selection in the dark sector.

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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