arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.09123astro-ph.CO
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$Λ$ CDM中两种冷流体的宇宙学扰动

Cosmological perturbations for two cold fluids in $Λ$CDM

Cornelius Rampf, Cora Uhlemann, Oliver Hahn

摘要:

我们宇宙的宇宙大尺度结构由重子和冷暗物质(CDM)组成。然而,人们习惯于把这两种成分看作压力为零的单一物质流体,这只有在足够大的尺度和足够晚的时代才是合理的。在这里,我们超越了单流体近似和发展的扰动理论的两个引力耦合流体,同时仍然假设消失的压力。我们主要研究$D$(或$D_+$)的幂微扰展开,即具有宇宙学常数$Λ$的$Λ$ CDM宇宙中物质的线性结构生长.我们特别导出(1)两种流体密度的显式递推关系,(2)拉格朗日坐标方法中的全阶互补结果,以及(3)宇宙大尺度结构半经典方法中的相关分量波函数。在我们的姊妹论文(Hahn et al. 2020)中,我们应用这些新的理论结果为宇宙学流体动力学模拟生成新的高阶初始条件。

英文摘要:

The cosmic large-scale structure of our Universe is comprised of baryons and cold dark matter (CDM). Yet it is customary to treat these two components as a combined single-matter fluid with vanishing pressure, which is justified only for sufficiently large scales and late times. Here we go beyond the single-fluid approximation and develop the perturbation theory for two gravitationally coupled fluids while still assuming vanishing pressure. We mostly focus on perturbative expansions in powers of $D$ (or $D_+$), the linear structure growth of matter in a $Λ$CDM Universe with cosmological constant $Λ$. We derive in particular (1) explicit recursion relations for the two fluid densities, (2) complementary all-order results in the Lagrangian-coordinates approach, as well as (3) the associated component wavefunctions in a semi-classical approach to cosmic large-scale structure. In our companion paper (Hahn et al. 2020) we apply these new theoretical results to generate novel higher-order initial conditions for cosmological hydrodynamical simulations.

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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