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arXiv 1002.4740astro-ph.CO
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用三维宇宙剪切测量统一暗物质

Measuring Unified Dark Matter with 3D Cosmic Shear

Stefano Camera, Thomas D. Kitching, Alan F. Heavens, Daniele Bertacca, Antonaldo Diaferio

摘要:

我们提出了一个统一的暗物质(UDM)模型,其中一个单一的标量场模拟暗物质(DM)和暗能量(DE)的未来三维宇宙剪切调查的参数估计预测。这些模型的优点是,它们可以用单一的物质成分来描述宇宙的动力学,为结构形成和宇宙加速提供解释。我们在这项工作中使用的UDM模型类的一个关键特征是由一个参数c_inf(以光速c=1为单位)表征,这是后期声速的值,并且结构形成取决于此。我们证明了DM样行为的标量场的属性可以估计与大规模的,完全三维弱透镜调查的精度非常高。我们发现,3D弱透镜显着约束c_inf,我们发现最小误差0.00003,为基准值c_inf=0.001,和0.000026,为c_inf=0.012。此外,我们计算了UDM模型在LCDM模型上的贝叶斯证据作为c_inf的函数。为此,我们可以将LCDM模型视为c_inf=0的UDM模型。我们发现,预期的证据清楚地表明,调查数据将毫无疑问地有利于UDM模型的LCDM模型,为值c_inf>0.001。

英文摘要:

We present parameter estimation forecasts for future 3D cosmic shear surveys for a class of Unified Dark Matter (UDM) models, where a single scalar field mimics both Dark Matter (DM) and Dark Energy (DE). These models have the advantage that they can describe the dynamics of the Universe with a single matter component providing an explanation for structure formation and cosmic acceleration. A crucial feature of the class of UDM models we use in this work is characterised by a parameter, c_inf (in units of the speed of light c=1), that is the value of the sound speed at late times, and on which structure formation depends. We demonstrate that the properties of the DM-like behaviour of the scalar field can be estimated with very high precision with large-scale, fully 3D weak lensing surveys. We found that 3D weak lensing significantly constrains c_inf, and we find minimal errors 0.00003, for the fiducial value c_inf=0.001, and 0.000026, for c_inf=0.012. Moreover, we compute the Bayesian evidence for UDM models over the LCDM model as a function of c_inf. For this purpose, we can consider the LCDM model as a UDM model with c_inf=0. We find that the expected evidence clearly shows that the survey data would unquestionably favour UDM models over the LCDM model, for the values c_inf>0.001.

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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