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arXiv 1202.0449astro-ph.COgr-qc
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用Ia型超新星和伽马射线暴约束暗能量和光滑度参数

Constraining the dark energy and smoothness parameter with type Ia Supernovae and Gamma-Ray Bursts

V. C. Busti, R. C. Santos, J. A. S. Lima

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7 pages, 4 figures, corrected version accepted for publication in Physical Review D
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摘要：

在观测到的宇宙中存在的不均匀性修改了距离红移关系，从而影响了宇宙学测试的结果相比，假设空间均匀的模型。通过Zeldovich-Kantowski-Dyer-Roeder（ZKDR）方法对不均匀性进行建模，并引入一个唯象的光滑参数$α$，我们重新讨论了基于Ia型超新星和伽马射线暴（GRB）数据的宇宙参数约束。目前的分析仅限于一个平面$Λ$ CDM模型与合理的假设，$Λ$不结块。使用来自Union 2 Compilation Data的557个SNe Ia数据的$χ^{2}$分析（Amanullah { \it et al.} 2010）将参数对（$Ω_m, α$）约束为$Ω_m=0.27_{-0.03}^{+0.08}$（$2σ$）和$α\geq 0.25$。一个仅基于59个Hymphoid GRB的类似分析（Wei 2010）将物质密度参数限制为$Ω_m= 0.35^{+0.62}_{-0.24}$（$2σ$），而平滑度参数的所有值都是允许的。通过执行联合分析，发现$Ω_m = 0.27^{+0.06}_{-0.03}$和$α\geq 0.52$。作为一个一般的结果，虽然考虑到目前的伽玛射线暴数据不能单独约束的平滑$α$参数，我们的分析提供了一个有趣的宇宙学探测暗能量，即使在存在的不均匀性。

英文摘要：

The existence of inhomogeneities in the observed Universe modifies the distance-redshift relations thereby affecting the results of cosmological tests in comparison to the ones derived assuming spatially uniform models. By modeling the inhomogeneities through a Zeldovich-Kantowski-Dyer-Roeder (ZKDR) approach which is phenomenologically characterized by a smoothness parameter $α$, we rediscuss the constraints on the cosmic parameters based on Supernovae type Ia and Gamma-Ray Bursts (GRBs) data. The present analysis is restricted to a flat $Λ$CDM model with the reasonable assumption that $Λ$ does not clump. A $χ^{2}$-analysis using 557 SNe Ia data from the Union2 Compilation Data (Amanullah {\it et al.} 2010) constrains the pair of parameters ($Ω_m, α$) to $Ω_m=0.27_{-0.03}^{+0.08}$($2σ$) and $α\geq 0.25$. A similar analysis based only on 59 Hymnium GRBs (Wei 2010) constrains the matter density parameter to be $Ω_m= 0.35^{+0.62}_{-0.24}$ ($2σ$) while all values for the smoothness parameter are allowed. By performing a joint analysis, it is found that $Ω_m = 0.27^{+0.06}_{-0.03}$ and $α\geq 0.52$. As a general result, although considering that current GRB data alone cannot constrain the smoothness $α$ parameter our analysis provides an interesting cosmological probe for dark energy even in the presence of inhomogeneities.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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