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arXiv 0907.4860astro-ph.CO
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利用观测数据约束DGP重力场

Constraining DGP Gravity from Observational Data

Jun-Qing Xia

摘要:

目前我们宇宙的加速膨胀可能是由一种未知的能量成分(暗能量)或广义相对论的修正(修正引力)驱动的。本文重新讨论了一个唯象模型的约束条件,该模型介于纯\LambdaCDM模型和带附加参数α的Dvali-Gabadadze-Porrati(DGP)膜世界模型之间.结合宇宙微波背景辐射(CMB)、重子声学振荡(BAO)和Ia型超新星(SNIa),以及伽马射线暴(GRB)和线性增长因子(LGF)等高红移观测,我们得到了参数α=0.254 \pm 0.153(68% C. L.)的严格约束,这意味着平坦的DGP模型与当前的观测结果不相容,而纯\LambdaCDM模型仍然非常好地拟合数据。最后,我们以更高的精度模拟了未来的测量,发现与现有的约束相比,对α的约束可以提高两倍。

英文摘要:

The accelerating expansion of our universe at present could be driven by an unknown energy component (Dark Energy) or a modification of general relativity (Modified Gravity). In this note we revisit the constraints on a phenomenological model which interpolates between the pure \LambdaCDM model and the Dvali-Gabadadze-Porrati (DGP) braneworld model with an additional parameter α. Combining the cosmic microwave background (CMB), baryon acoustic oscillations (BAO) and type Ia supernovae (SNIa), as well as some high-redshift observations, such as the gamma-ray bursts (GRB) and the measurements of linear growth factors (LGF), we obtain the tight constraint on the parameter α=0.254\pm0.153 (68% C.L.), which implies that the flat DGP model is incompatible with the current observations, while the pure \LambdaCDM model still fits the data very well. Finally, we simulate the future measurements with higher precisions and find that the constraint on αcan be improved by a factor two, when compared to the present constraints.

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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