从矮星系到大质量星系的暗物质晕：与ΛCDM流体动力学模拟不存在系统性的内密度张力
Dark matter haloes from dwarf to massive galaxies: no systematic inner-density tension with ΛCDM hydrodynamical simulations
- Leiden University（莱顿大学）
- University of Surrey（萨里大学）
- Instituto de Astrofísica de Canarias (IAC)（加那利天体物理研究所）
- Universidad de La Laguna（拉帕鲁纳大学）
- Stockholm University（斯德哥尔摩大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究分析48个富气星系和8个贫气卫星星系样本，发现其内暗物质密度与ΛCDM流体动力学模拟大体一致，无系统性张力，从而缓解了尖点-核球和旋转曲线多样性问题。
AI中文摘要：
冷暗物质（CDM）范式中两个最突出的小尺度挑战是尖点-核球问题和旋转曲线多样性问题。前者涉及许多星系中观测到的浅内暗物质密度轮廓，与无碰撞CDM预测的尖点形成对比；后者则涉及观测推断出的内暗物质密度和旋转曲线形状的范围，比流体动力学模拟传统上再现的范围更广。因此，对暗物质核大小和晕密度的稳健观测约束对于检验暗物质的本质和星系形成过程的影响都至关重要。我们分析了精心挑选的48个富气星系和8个银河系贫气卫星星系样本的内暗物质分布，跨越了$M_\ast$的6个数量级。我们发现暗物质核大小和核化程度存在显著离散，尖点和核球晕在广泛的$M_\ast$范围内均出现。这些核在能量上与恒星反馈一致，所需的超新星能量耦合效率约为$0.1-1\\%$。与NIHAO、FIRE-2和EDGE模拟的比较显示，观测星系和模拟星系的内暗物质密度和对数斜率大体一致。主要的残余差异涉及一些大质量模拟星系的陡峭斜率以及SHMR的差异。使用先前工作中的旋转曲线多样性诊断，我们发现极端差异在我们的精选样本中不存在，且主要归因于不确定的运动学或重子质量分布。在我们的分析范围内，我们未发现星系样本与当前$\Lambda$CDM流体动力学模拟之间存在系统性内密度张力的证据。加上核形成的适度能量需求，这大大缓解了尖点-核球问题和旋转曲线多样性问题。
英文摘要：
Two of the most prominent small-scale challenges to the cold dark matter (CDM) paradigm are the cusp-core and diversity-of-rotation-curves problems. The former concerns the shallow inner DM density profiles inferred for many galaxies compared with the cusps predicted by collisionless CDM, while the latter concerns the wider range of inner DM densities and rotation curve shapes inferred observationally than hydrodynamical simulations traditionally reproduce. Robust observational constraints on DM core sizes and halo densities are therefore essential for testing both the nature of DM and the impact of galaxy formation processes. We analyse the inner DM distribution of a curated sample of 48 gas-rich galaxies and 8 Milky Way gas-poor satellites, spanning 6 orders of magnitude in $M_\ast$. We find substantial scatter in DM core sizes and degrees of coreness, with both cuspy and cored haloes occurring over a broad $M_\ast$ range. The cores are energetically consistent with stellar feedback, requiring modest supernova energy coupling efficiencies of order $0.1-1\%$. Comparisons with the NIHAO, FIRE-2, and EDGE simulations reveal broad agreement in the inner DM densities and logarithmic slopes of observed and simulated galaxies. The main residual differences concern the steep slopes of some massive simulated galaxies and differences in SHMRs. Using a rotation-curve diversity diagnostic from previous work, we find that extreme discrepancies with simulations are absent from our curated sample and largely attributable to uncertain kinematics or baryonic mass distributions. Within the scope of our analysis, we find no evidence of a systematic inner-density tension between our galaxy sample and current $Λ$CDM hydrodynamical simulations. Together with the modest energetic requirements for core formation, this substantially alleviates the cusp-core and diversity-of-rotation-curves problems.
