Comparing the VGCG model as the unification of dark sectors with observations
Comparing the VGCG model as the unification of dark sectors with observations
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DOI：
10.1007/s11433-013-5300-5
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发表时间：
2014-03
期刊：
影响因子：
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通讯作者：
Jianbo Lu;LiDong Chen;Lixin Xu;Tianqiang Li
中科院分区：
文献类型：
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作者：
Jianbo Lu;LiDong Chen;Lixin Xu;Tianqiang Li
目前的观测表明，宇宙中95%的能量密度是未知的暗成分。暗成分被认为是由两种流体组成：暗物质和暗能量。或者它是这两种暗成分的混合物，也就是说，我们可以认为它是一种外来的未知暗流体。考虑到这一点，本文研究了不将未知流体划分为暗物质和暗能量部分的变量广义Chaplygin气体（VGCG）模型。通过使用马尔可夫链蒙特卡罗方法,VGCG模型的统一黑暗领域限制,VGCG模型参数和约束的结果是,n = 0.00057−0.0006−0.0006 + 0.0001 + 0.0009,α= 0.0015−0.0015−0.0015 + 0.0003 + 0.0017 andbs = 0.778−0.016−0.035 + 0.016 + 0.030,通过宇宙微波背景7 WMAP数据完整的数据点,重子声学振荡斯隆数字巡天数据(SDSS)和二场星系红移(2 dfgrs)调查中,以及存在系统误差的Union2型Ia超新星数据。最后，根据减速参数的演化，证明了在VGCG宇宙学中可以得到从减速到加速的膨胀宇宙。
Current observations indicate that 95% of the energy density in the universe is the unknown dark component. The dark component is considered composed of two fluids: dark matter and dark energy. Or it is a mixture of these two dark components, i.e., one can consider it an exotic unknown dark fluid. With this consideration, the variable generalized Chaplygin gas (VGCG) model is studied with not dividing the unknown fluid into dark matter and dark energy parts in this paper. By using the Markov Chain Monte Carlo method, the VGCG model as the unification of dark sectors is constrained, and the constraint results on the VGCG model parameters are,n= 0.00057−0.0006−0.0006+0.0001+0.0009,α= 0.0015−0.0015−0.0015+0.0003+0.0017andBs= 0.778−0.016−0.035+0.016+0.030, obtained by the cosmic microwave background data from the 7-year WMAP full data points, the baryon acoustic oscillation data from Sloan Digital Sky Survey (SDSS) and 2-degree Field Galaxy Redshift (2dFGRS) survey, and the Union2 type Ia supernova data with systematic errors. At last, according to the evolution of deceleration parameter it is shown that an expanded universe from deceleration to acceleration can be obtained in VGCG cosmology.