Cold dark matter: Controversies on small scales
Cold dark matter: Controversies on small scales
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DOI：
10.1073/pnas.1308716112
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
D. Weinberg;J. Bullock;F. Governato;Rachel Kuzio de Naray;A. Peter
中科院分区：
文献类型：
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作者：
D. Weinberg;J. Bullock;F. Governato;Rachel Kuzio de Naray;A. Peter
冷暗物质（CDM）宇宙学模型在解释巨大红移范围内的宇宙结构方面非常成功，但它面临着来自探测暗物质晕最内部区域和银河系矮星系卫星属性的观测的持续挑战。我们回顾了目前的观测和理论状态，这些“小规模的争议。”宇宙学模拟，仅包括重力和碰撞的CDM预测晕丰富的子结构和中心密度太高，以匹配星系动力学的约束。解决方案可能存在于重子物理学中：最近的数值模拟和分析模型表明，与有效的超新星反馈有关的引力势波动可以使大质量星系中晕的中心尖变平，反馈和低星星形成效率的结合可以解释为什么大多数围绕银河系运行的暗物质subhalo没有可见星系。然而，目前尚不清楚这种解决方案是否适用于最低质量的星系，在那里观察到差异。或者，小规模的冲突可能是暗区本身更复杂物理学的证据。例如，来自强暗物质自相互作用的弹性散射可以改变预测的晕质量分布，从而与广泛的星系质量范围内的观测结果保持良好的一致性。引力透镜效应和恒星晕中潮汐流的动力学扰动提供了证据，证明了低质量晕的丰富人口与CDM的预测雅阁。这些观测方法将在未来几年变得更加强大。
The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. We review the current observational and theoretical status of these “small-scale controversies.” Cosmological simulations that incorporate only gravity and collisionless CDM predict halos with abundant substructure and central densities that are too high to match constraints from galaxy dynamics. The solution could lie in baryonic physics: Recent numerical simulations and analytical models suggest that gravitational potential fluctuations tied to efficient supernova feedback can flatten the central cusps of halos in massive galaxies, and a combination of feedback and low star formation efficiency could explain why most of the dark matter subhalos orbiting the Milky Way do not host visible galaxies. However, it is not clear that this solution can work in the lowest mass galaxies, where discrepancies are observed. Alternatively, the small-scale conflicts could be evidence of more complex physics in the dark sector itself. For example, elastic scattering from strong dark matter self-interactions can alter predicted halo mass profiles, leading to good agreement with observations across a wide range of galaxy mass. Gravitational lensing and dynamical perturbations of tidal streams in the stellar halo provide evidence for an abundant population of low-mass subhalos in accord with CDM predictions. These observational approaches will get more powerful over the next few years.