Warm dark matter at small scales: peculiar velocities and phase space density.
Warm dark matter at small scales: peculiar velocities and phase space density.
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小尺度的暖暗物质：特殊的速度和相空间密度。
DOI：
10.1103/physrevd.83.103504
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发表时间：
2010
影响因子：
5
通讯作者：
D. Boyanovsky
中科院分区：
文献类型：
--
作者：
D. Boyanovsky
我们研究的规模和红移依赖的功率谱的密度扰动和特有的速度，和一个粗粒度的相空间密度的演化（WDM）粒子，在辐射占主导地位的阶段解耦。的（WDM）的修正获得在一个微扰膨胀有效的红移范围内的N体模拟设置初始条件，并为广泛的尺度。红移依赖性由去耦时分布函数的峰度决定。在大的红移下，对于ε 2 > 1，有一个特殊速度的增强，这有助于自由流，并导致物质功率谱的进一步抑制和在小于自由流尺度的尺度上特殊速度自相关函数的增强。在这些尺度上，特殊速度的统计涨落也被同样的效应所抑制。在线性化近似下，粗粒相空间密度具有由密度扰动功率谱确定的引力扰动的红移相关（WDM）校正和2。对于φ 2 > 25/21，它随着比例因子的增长而增长，这是抑制统计波动的结果。详细研究了WDM的两种具体模型。（WDM）修正放宽了质量的界限。
We study the scale and redshift dependence of the power spectra for density perturbations and peculiar velocities, and the evolution of a coarse grained phase space density for (WDM) particles that decoupled during the radiation dominated stage. The (WDM) corrections are obtained in a perturbative expansion valid in the range of redshifts at which N-body simulations set up initial conditions, and for a wide range of scales. The redshift dependence is determined by the kurtosis �2 of the distribution function at decoupling. At large redshift there is an enhancement of peculiar velocities for �2 > 1 that contributes to free streaming and leads to further suppression of the matter power spectrum and an enhancement of the peculiar velocity autocorrelation function at scales smaller than the free streaming scale. Statistical fluctuations of peculiar velocities are also suppressed on these scales by the same effect. In the linearized approximation, the coarse grained phase space density features redshift dependent (WDM) corrections from gravitational perturbations determined by the power spectrum of density perturbations and �2. For �2 > 25/21 it grows logarithmically with the scale factor as a consequence of the suppression of statistical fluctuations. Two specific models for WDM are studied in detail. The (WDM) corrections relax the bounds on the mass.