arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1106.0299astro-ph.CO
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从膨胀历史和结构增长的未来测量中得到的暗能量和中微子质量

Dark Energy and Neutrino Masses from Future Measurements of the Expansion History and Growth of Structure

Shahab Joudaki, Manoj Kaplinghat

摘要:

我们预测的宇宙学约束的组合探针的普遍膨胀率和物质扰动的增长,在弱透镜层析成像,星系层析成像,超新星的形式,和宇宙微波背景纳入所有的交叉相关性之间的观测量的一个广泛的宇宙学参数集。我们允许非零曲率和参数化我们的无知的早期宇宙,允许一个不可忽略的部分暗能量(DE)在高红移。我们发现,早期DE密度可以被约束到0.2%的临界密度的宇宙与普朗克结合地面LSST的调查,而曲率可以被约束到0.06%。然而,这些额外的自由度降低了我们测量晚期暗能量和中微子质量总和的能力。我们发现,宇宙学探针的组合可以打破简并和限制中微子质量的总和为0.04 eV,目前DE密度也到0.2%的临界密度,和状态方程为0.01 -大约两个退化的约束的情况下,不允许早期DE相比,整体的一个因素。天基飞行任务的制约因素是类似的。即使是在高红移临界密度的1%的暗能量分数,如果在未来的分析中没有考虑,宇宙学参数的偏差高达2西格玛。我们的分析表明,当多个宇宙学探测器结合在一起时,抛弃非线性尺度(多极> 1000)可能不会导致未来参数测量的显著退化。我们发现,包括不同的探针之间的互相关可以导致改进的约束的中微子质量和早期的暗能量密度的总和的2倍。

英文摘要:

We forecast the expected cosmological constraints from a combination of probes of both the universal expansion rate and matter perturbation growth, in the form of weak lensing tomography, galaxy tomography, supernovae, and the cosmic microwave background incorporating all cross-correlations between the observables for an extensive cosmological parameter set. We allow for non-zero curvature and parameterize our ignorance of the early universe by allowing for a non-negligible fraction of dark energy (DE) at high redshifts. We find that early DE density can be constrained to 0.2% of the critical density of the universe with Planck combined with a ground-based LSST-like survey, while curvature can be constrained to 0.06%. However, these additional degrees of freedom degrade our ability to measure late-time dark energy and the sum of neutrino masses. We find that the combination of cosmological probes can break degeneracies and constrain the sum of neutrino masses to 0.04 eV, present DE density also to 0.2% of the critical density, and the equation of state to 0.01 - roughly a factor of two degradation in the constraints overall compared to the case without allowing for early DE. The constraints for a space-based mission are similar. Even a modest 1% dark energy fraction of the critical density at high redshift, if not accounted for in future analyses, biases the cosmological parameters by up to 2 sigma. Our analysis suggests that throwing out nonlinear scales (multipoles > 1000) may not result in significant degradation in future parameter measurements when multiple cosmological probes are combined. We find that including cross-correlations between the different probes can result in improved constraints by up to a factor of 2 for the sum of neutrino masses and early dark energy density.

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