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arXiv 1202.0353astro-ph.CO
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未来大尺度观测对统一暗物质模型的包含约束

Inclusive Constraints on Unified Dark Matter Models from Future Large-Scale Surveys

Stefano Camera, Carmelita Carbone, Lauro Moscardini

摘要:

在过去的几年里,宇宙中的暗成分-暗物质和暗能量-的性质由一个单一的“暗流体”来解释的宇宙学模型引起了越来越多的关注和兴趣。在众多的提议中,统一暗物质(UDM)宇宙学是有希望成为有效理论的候选者。在这些模型中,一个标量场的拉格朗日函数中含有一个非正则动力学项,它既模拟了宇宙后期的加速膨胀,又模拟了宇宙大尺度结构的聚集特性。然而,UDM模型也提出了特殊的行为,最有趣的是,在标量场的暗物质分量的扰动确实有一个不可忽略的声速的事实。这就产生了一个有效的牛顿势的金斯标度,低于这个标度,暗流体就不再聚集。这意味着增长的结构相当不同的和谐LCDM模型。在本文中,我们证明了即将到来的大规模调查将能够区分可行的UDM模型和LCDM到一个很好的准确度。为此目的,计划中的欧几里德卫星将是一个强有力的工具,因为它将提供关于星系聚集和宇宙切变的弱透镜效应的非常精确的数据。最后,我们还利用正在进行的CMB普朗克实验的约束力。虽然我们的方法是最保守的,只包含了很好理解的线性动力学,最后,我们也展示了如果包含了一些非线性信息,可以做些什么。

英文摘要:

In the very last years, cosmological models where the properties of the dark components of the Universe - dark matter and dark energy - are accounted for by a single "dark fluid" have drawn increasing attention and interest. Amongst many proposals, Unified Dark Matter (UDM) cosmologies are promising candidates as effective theories. In these models, a scalar field with a non-canonical kinetic term in its Lagrangian mimics both the accelerated expansion of the Universe at late times and the clustering properties of the large-scale structure of the cosmos. However, UDM models also present peculiar behaviours, the most interesting one being the fact that the perturbations in the dark-matter component of the scalar field do have a non-negligible speed of sound. This gives rise to an effective Jeans scale for the Newtonian potential, below which the dark fluid does not cluster any more. This implies a growth of structures fairly different from that of the concordance LCDM model. In this paper, we demonstrate that forthcoming large-scale surveys will be able to discriminate between viable UDM models and LCDM to a good degree of accuracy. To this purpose, the planned Euclid satellite will be a powerful tool, since it will provide very accurate data on galaxy clustering and the weak lensing effect of cosmic shear. Finally, we also exploit the constraining power of the ongoing CMB Planck experiment. Although our approach is the most conservative, with the inclusion of only well-understood, linear dynamics, in the end we also show what could be done if some amount of non-linear information were included.

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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