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arXiv 1006.4845astro-ph.CO
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用斯隆数字巡天测量的明亮红色星系功率谱和微扰理论的中微子质量约束

Neutrino mass constraint with the Sloan Digital Sky Survey power spectrum of luminous red galaxies and perturbation theory

Shun Saito, Masahiro Takada, Atsushi Taruya

摘要:

我们比较模型的功率谱,微扰理论(PT)的基础上计算的发光的红色星系(LRG)的功率谱测量的SDSSDR 7目录,假设一个平坦的,CDM主导的宇宙学。该模型包括大质量中微子的影响,非线性的物质聚集和非线性的,尺度依赖的星系偏置在一个自洽的方式。我们首先测试PT模型的准确性,通过比较模型预测的真实和红移空间中的晕功率谱测量模拟没有大量的中微子。我们发现,PT模型与偏置参数进行适当调整,可以相当好地再现模拟结果。结果表明,在统计不确定性的范围内,如果使用k~0.15h/Mpc的功率谱信息,由假设参数拟合得到的最佳拟合参数可以恢复模拟中的输入宇宙学参数,包括中微子质量的上限。然而,对于红移空间的功率谱,当使用k~0.2h/Mpc的信息时,最佳拟合的宇宙学参数显示出与输入值相当大的偏差,这可能是由于非线性红移畸变效应。鉴于这些测试,我们决定,作为保守的选择,使用LRG功率谱高达k=0.1h/Mpc,以尽量减少可能的未知非线性效应。结合Wilkinson微波背景各向异性探测器(WMAP)的最新结果,我们导出了中微子质量和的一个可靠的上界:m_nu,tot < 0.81eV(95% C.L.),相对于包括非线性偏置参数和暗能量状态方程参数的其它参数被边缘化。中微子的质量极限比单独使用WMAP 5的极限提高了1.85倍,m_nu,tot < 1.5eV。

英文摘要:

We compare the model power spectrum, computed based on perturbation theory (PT) with the power spectrum of luminous red galaxies (LRG) measured from the SDSSDR7 catalog, assuming a flat, CDM-dominated cosmology. The model includes the effects of massive neutrinos, nonlinear matter clustering and nonlinear, scale-dependent galaxy bias in a self-consistent manner. We first test the accuracy of PT-model by comparing the model predictions with the halo power spectrum in real- and redshift-space measured from simulations without massive neutrinos. We show that the PT-model with bias parameters being properly adjusted can fairly well reproduce the simulation results. As a result the best-fit parameters obtained from the hypothetical parameter fitting recover, within statistical uncertainties, the input cosmological parameters in simulations, including an upper bound on neutrino mass, if the power spectrum information up to k~0.15h/Mpc is used. However, for the redshift-space power spectrum, the best-fit cosmological parameters show a sizable bias from the input values if using the information up to k~0.2h/Mpc, probably due to nonlinear redshift distortion effect. Given these tests, we decided, as a conservative choice, to use the LRG power spectrum up to k=0.1h/Mpc in order to minimize possible unknown nonlinearity effects. In combination with the recent results from Wilkinson Microwave Background Anisotropy Probe (WMAP), we derive a robust upper-bound on the sum of neutrino masses, given as m_nu,tot < 0.81eV (95% C.L.), marginalized over other parameters including nonlinear bias parameters and dark energy equation of state parameter. The neutrino mass limit is improved by a factor of 1.85 compared to the limit from the WMAP5 alone, m_nu,tot < 1.5eV.

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