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arXiv 1806.07653astro-ph.COgr-qchep-ph
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约束暗能量状态方程中的晚期跃迁

Constraining late-time transitions in the dark energy equation of state

C. J. A. P. Martins, M. Prat Colomer

摘要:

观测宇宙学最引人注目的目标之一是描述暗能量成分的特性,包括其可能的动力学,暗能量成分被认为是宇宙最近加速的原因。在这项工作中,我们研究的现象,但物理动机类的模型,其中的暗能量状态方程可以在低红移进行快速过渡,也许与发病的加速阶段本身。通过一个标准的统计分析,我们已经使用了低红移宇宙学数据,来自Ia型超新星和哈勃参数测量,这些可能的转变以及对这些模型中的暗能量状态方程的当前值和渐近过去的陡度设置约束。我们还研究了这些约束取决于所使用的特定参数化的方式。我们的研究结果证实,这种后期的转变是强烈的约束。如果需要一个类似于物质的预跃迁行为,那么跃迁被限制在高红移处(在物质时代有效),而如果预跃迁状态方程是一个自由参数,那么它被限制在接近宇宙学常数。在任何情况下,暗能量状态方程的值在今天附近也必须非常类似于一个宇宙学常数。总的结论是,这种行为的任何重大偏离都只会发生在深物质时代,因此没有证据表明与加速开始相关的转变。因此,能够探测深物质时代宇宙动力学的观测工具尤为重要。

英文摘要:

One of the most compelling goals of observational cosmology is the characterisation of the properties of the dark energy component thought to be responsible for the recent acceleration of the universe, including its possible dynamics. In this work we study phenomenological but physically motivated classes of models in which the dark energy equation of state can undergo a rapid transition at low redshifts, perhaps associated with the onset of the acceleration phase itself. Through a standard statistical analysis we have used low-redshift cosmological data, coming from Type Ia supernova and Hubble parameter measurements, to set constraints on the steepness of these possible transitions as well as on the present-day values of the dark energy equation of state and in the asymptotic past in these models. We have also studied the way in which these constraints depend on the specific parametrisation being used. Our results confirm that such late-time transitions are strongly constrained. If one demands a matter-like pre-transition behaviour, then the transition is constrained to occur at high redshifts (effectively in the matter era), while if the pre-transition equation of state is a free parameter then it is constrained to be close to that of a cosmological constant. In any case, the value of dark energy equation of state near the present day must also be very similar to that of a cosmological constant. The overall conclusion is that any significant deviations from this behaviour can only occur in the deep matter era, so there is no evidence for a transition associated with the onset of acceleration. Observational tools capable of probing the dynamics of the universe in the deep matter era are therefore particularly important.

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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