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arXiv 0706.0938astro-ph
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用伽马射线暴和其他宇宙学探测器测量暗能量

Measuring Dark Energy with Gamma-Ray Bursts and Other Cosmological Probes

F. Y. Wang, Z. G. Dai, Zong-Hong Zhu

备注：
28 pages, 13 figures, accepted for publication in ApJ. One reference added, one minor change in the final paragraph of section 1
发表信息：
Astrophys.J.667:1-10,2007
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摘要：

利用Ia型超新星（SNe Ia）、宇宙微波背景（CMB）各向异性、Sloan数字巡天（SDSS）的重子声学振荡（BAO）峰值、星系团中X射线气体质量分数以及2dF星系红移巡天（2dF Galaxy Redshift Survey）的z=0.15处微扰线性增长率等数据，可以对宇宙学参数和暗能量进行约束。最近，伽马射线暴（GRB）也被认为是有前途的宇宙学标准烛光。本文结合最近一个包含69个事件的伽玛暴样本和其他宇宙学探测结果，给出了宇宙学参数和暗能量的约束条件。首先，我们发现，对于LambdaCDM宇宙学，这种组合使得约束严格，最佳拟合接近平坦宇宙。其次，我们拟合了平坦的卡达西膨胀模型，发现这个模型与LambdaCDM宇宙学是一致的。第三，我们提出了几个双参数暗能量模型的限制，并发现这些模型也符合LambdaCDM宇宙学。最后，我们重建了暗能量状态方程参数w（z）和减速参数q（z）。我们看到，加速可以从z_T=0.40_{-0.08}^{+0.14}到z_T=0.65_{-0.05}^{+0.10}的红移开始。这种跃迁红移的差异是由于我们采用了不同的暗能量模型。对w（z）的最严格的约束位于z \sim 0.3-0.6的红移范围内。

英文摘要：

It has been widely shown that the cosmological parameters and dark energy can be constrained by using data from type-Ia supernovae (SNe Ia), the cosmic microwave background (CMB) anisotropy, the baryon acoustic oscillation (BAO) peak from Sloan Digital Sky Survey (SDSS), the X-ray gas mass fraction in clusters, and the linear growth rate of perturbations at z=0.15 as obtained from the 2dF Galaxy Redshift Survey. Recently, gamma-ray bursts (GRBs) have also been argued to be promising standard candles for cosmography. In this paper, we present constraints on the cosmological parameters and dark energy by combining a recent GRB sample including 69 events with the other cosmological probes. First, we find that for the LambdaCDM cosmology this combination makes the constraints stringent and the best fit is close to the flat universe. Second, we fit the flat Cardassian expansion model and find that this model is consistent with the LambdaCDM cosmology. Third, we present constraints on several two-parameter dark energy models and find that these models are also consistent with the LambdaCDM cosmology. Finally, we reconstruct the dark energy equation-of-state parameter w(z) and the deceleration parameter q(z). We see that the acceleration could have started at a redshift from z_T=0.40_{-0.08}^{+0.14} to z_T=0.65_{-0.05}^{+0.10}. This difference in the transition redshift is due to different dark energy models that we adopt. The most stringent constraint on w(z) lies in the redshift range z\sim 0.3-0.6.

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