The dark energy plus cold dark matter (ΛCDM) cosmological model has been a demonstrably successful framework for predicting and explaining the large-scale structure of the Universe and its evolution with time. Yet on length scales smaller than ∼1 Mpc and mass scales smaller than ∼1011M⊙, the theory faces a number of challenges. For example, the observed cores of many dark matter–dominated galaxies are both less dense and less cuspy than naively predicted in ΛCDM. The number of small galaxies and dwarf satellites in the Local Group is also far below the predicted count of low-mass dark matter halos and subhalos within similar volumes. These issues underlie the most well-documented problems with ΛCDM: cusp/core, missing satellites, and too-big-to-fail. The key question is whether a better understanding of baryon physics, dark matter physics, or both is required to meet these challenges. Other anomalies, including the observed planar and orbital configurations of Local Group satellites and the tight baryonic...

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ΛCDM 范式的小规模挑战

暗能量加冷暗物质 (ΛCDM) 宇宙学模型已成为预测和解释宇宙大尺度结构及其随时间演化的一个明显成功的框架。然而，在小于~1 Mpc 的长度尺度和小于~1011M⊙ 的质量尺度上，该理论面临着许多挑战。例如，与 ΛCDM 天真预测的相比，观察到的许多暗物质主导星系的核心既不那么密集，也不那么尖锐。本星系群中小星系和矮卫星的数量也远低于预测的类似体积内的低质量暗物质晕和亚晕的数量。这些问题是 ΛCDM 最有据可查的问题的基础：尖点/核心、缺少卫星和太大而不能失败。关键问题是能否更好地理解重子物理学、暗物质物理学、或两者都需要应对这些挑战。其他异常，包括观察到的本地群卫星的平面和轨道配置​​以及紧密的重子...