Observational constraints on cosmic neutrinos and dark energy revisited
Observational constraints on cosmic neutrinos and dark energy revisited
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DOI：
10.1088/1475-7516/2012/11/018
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发表时间：
2012
影响因子：
6.4
通讯作者：
Xin Wang;Xiao-Lei Meng;Tong-Jie Zhang;HuanYuan Shan;Yan Gong;Charling Tao;Xuelei Chen;Y.F. Huang
中科院分区：
文献类型：
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作者：
Xin Wang;Xiao-Lei Meng;Tong-Jie Zhang;HuanYuan Shan;Yan Gong;Charling Tao;Xuelei Chen;Y.F. Huang
利用宇宙微波背景各向异性（WMAP）、弱引力透镜（CFHTLS）、重子声学振荡测量（SDSS+WiggleZ）、最新的哈勃观测参数数据、Ia型超新星的Union2.1编译和HST先验，我们对中微子质量和（Sigma m(v)）、中微子有效种数（N-eff）和暗能量状态方程(w)施加了约束。无论是个人还是集体。我们发现，如果N-eff和w是固定的，则可以从完整的数据组合中提取Sigma m(v)的严格上限。然而，如果允许N-eff和w变化，这个上界就被严重削弱了。这一结果自然提出了以往文献中报道的Sigma m(v)严格上界的鲁棒性问题。我们最广义约束的最佳拟合值为σ m(v) = 0.556(-0.288)(+0.231) eV, N-eff = 3.839 +/- 0.452, w = -1.058 +/- 0.088，置信度为68%，显示了中微子总质量的下限，有利于额外的轻自由度，并支持宇宙常数模型。目前的弱透镜数据已经有助于约束固定w的宇宙学模型参数。当w = -1时，哈勃参数数据集比超新星具有许多优势，特别是它在约束N-eff方面的照明能力。只要包含w作为自由参数，在参数约束中起主导作用的仍然是Ia型超新星的可标准化烛光。
Using several cosmological observations, i.e. the cosmic microwave background anisotropies (WMAP), the weak gravitational lensing (CFHTLS), the measurements of baryon acoustic oscillations (SDSS+WiggleZ), the most recent observational Hubble parameter data, the Union2.1 compilation of type Ia supernovae, and the HST prior, we impose constraints on the sum of neutrino masses (Sigma m(v)), the effective number of neutrino species (N-eff) and dark energy equation of state (w), individually and collectively. We find that a tight upper limit on Sigma m(v) can be extracted from the full data combination, if N-eff and w are fixed. However this upper bound is severely weakened if N-eff and w are allowed to vary. This result naturally raises questions on the robustness of previous strict upper bounds on Sigma m(v), ever reported in the literature. The best-fit values from our most generalized constraint read Sigma m(v) = 0.556(-0.288)(+0.231) eV, N-eff = 3.839 +/- 0.452, and w = -1.058 +/- 0.088 at 68% confidence level, which shows a firm lower limit on total neutrino mass, favors an extra light degree of freedom, and supports the cosmological constant model. The current weak lensing data are already helpful in constraining cosmological model parameters for fixed w. The dataset of Hubble parameter gains numerous advantages over supernovae when w = -1, particularly its illuminating power in constraining N-eff. As long as w is included as a free parameter, it is still the standardizable candles of type Ia supernovae that play the most dominant role in the parameter constraints.