Predicting the density profiles of the first halos
Predicting the density profiles of the first halos
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DOI：
10.1103/physrevd.100.023523
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发表时间：
2019-05
影响因子：
5
通讯作者：
M. Sten Delos;M. Bruff;A. Erickcek
中科院分区：
文献类型：
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作者：
M. Sten Delos;M. Bruff;A. Erickcek
第一批暗物质晕是由物质密度场中的峰值直接坍塌形成的，来自数值模拟和其他分析的证据表明，这些天体的密集内部区域至今仍在很大程度上存在。这些光晕将是宇宙中最密集的暗物质结构，它们的丰度可以探测在原始密度场上留下印记的过程，例如膨胀或早期物质主导的时代。他们还可以通过暗物质的自由流动尺度来探测暗物质。从ρ∝r-3/2内部密度分布可以看出，第一个晕定性地不同于通过等级聚类形成的晕.在这项工作中，我们提出并调整了预测这些晕的密度分布的模型，这些模型从这些晕坍塌的密度峰的性质中预测它们的密度分布。这些模型预测了密度分布的ρ=Ar-3/2小半径渐近线的系数A以及最大圆速度Vmax和相关的半径Rmax。这些模型是通用的；它们可以应用于任何宇宙学，我们通过使用在截然不同的宇宙学场景中进行的六个N体模拟来验证它们，以证实这一点。我们发现，这些模型甚至可以在功率谱支持较窄的情况下以合理的精度预测整个晕群，尽管对于更广泛的功率谱，需要了解晕合并的影响。随着它们与原始密度场的联系建立起来，第一批暗物质光晕将作为早期宇宙和暗物质性质的探测器。
The first dark matter halos form by direct collapse from peaks in the matter density field, and evidence from numerical simulations and other analyses suggests that the dense inner regions of these objects largely persist today. These halos would be the densest dark matter structures in the Universe, and their abundance can probe processes that leave imprints on the primordial density field, such as inflation or an early matter-dominated era. They can also probe dark matter through its free-streaming scale. The first halos are qualitatively different from halos that form by hierarchical clustering, as evidenced by their ρ∝r-3/2 inner density profiles. In this work, we present and tune models that predict the density profiles of these halos from properties of the density peaks from which they collapsed. These models predict the coefficient A of the ρ=Ar-3/2 small-radius asymptote of the density profile along with the maximum circular velocity vmax and associated radius rmax. These models are universal; they can be applied to any cosmology, and we confirm this by validating them using six N-body simulations carried out in wildly disparate cosmological scenarios. We find that these models can even predict the full population of halos with reasonable accuracy in scenarios with narrowly supported power spectra, although for broader power spectra, an understanding of the impact of halo mergers is needed. With their connection to the primordial density field established, the first dark matter halos will serve as probes of the early Universe and the nature of dark matter.