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arXiv 1109.3172astro-ph.COhep-ph
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基于当前观测数据的暗能量约束的比较研究

A Comparative Study of Dark Energy Constraints from Current Observational Data

Yun Wang, Chia-Hsun Chuang, Pia Mukherjee

摘要:

我们研究如何从目前的观测数据的暗能量的限制取决于所使用的分析方法:Ia型超新星(SNe Ia)的分析,和星系聚类数据。我们推广了Ia型超新星的通量平均分析方法,允许Ia型超新星的相关误差,以减少由于Ia型超新星的弱透镜效应而引起的系统偏差。我们发现,通量平均导致更大的误差暗能量和宇宙学参数,如果只使用超新星Ia数据。当SN Ia数据(SNLS团队的最新汇编)与WMAP 7年结果相结合(根据我们对CMB位移参数的概率分布的高斯拟合)、哈勃空间望远镜(HST)最新的哈勃常数(H_0)测量和伽马射线暴(GRB)数据,Ia超新星的通量平均增加了与其他数据的一致性,并导致对z=1处的暗能量密度和宇宙曲率Ω_k的明显更严格的约束。H星系团的测量(z=0.35)r_s(z_d)和r_s(z_d)/D_A(z=0.35)(其中H(z)是哈勃参数,D_A(z)是角直径距离,r_s(z_d)是拖曳时期的声音视界)与SN Ia数据一致,给出了相同的pirors(CMB+H_0+GRB),并导致显着改善暗能量约束时,组合。目前的数据完全符合一个宇宙学常数和一个平坦的宇宙。

英文摘要:

We examine how dark energy constraints from current observational data depend on the analysis methods used: the analysis of Type Ia supernovae (SNe Ia), and that of galaxy clustering data. We generalize the flux-averaging analysis method of SNe Ia to allow correlated errors of SNe Ia, in order to reduce the systematic bias due to weak lensing of SNe Ia. We find that flux-averaging leads to larger errors on dark energy and cosmological parameters if only SN Ia data are used. When SN Ia data (the latest compilation by the SNLS team) are combined with WMAP 7 year results (in terms of our Gaussian fits to the probability distributions of the CMB shift parameters), the latest Hubble constant (H_0) measurement using the Hubble Space Telescope (HST), and gamma ray burst (GRB) data, flux-averaging of SNe Ia increases the concordance with other data, and leads to significantly tighter constraints on the dark energy density at z=1, and the cosmic curvature Ω_k. The galaxy clustering measurements of H(z=0.35)r_s(z_d) and r_s(z_d)/D_A(z=0.35) (where H(z) is the Hubble parameter, D_A(z) is the angular diameter distance, and r_s(z_d) is the sound horizon at the drag epoch) by Chuang & Wang (2011) are consistent with SN Ia data, given the same pirors (CMB+H_0+GRB), and lead to significantly improved dark energy constraints when combined. Current data are fully consistent with a cosmological constant and a flat universe.

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