发表机构
Shanghai Astronomical Observatory, Chinese Academy of Sciences; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences; Dipartimento di Fisica e Astronomia “Augusto Righi”, Alma Mater Studiorum Università di Bologna; INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna; INFN-Sezione di Bologna; State Key Laboratory of Radio Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences; School of Physics and Astronomy, Beijing Normal University; Department of Astronomy, Tsinghua University（中国科学院上海天文台; 中国科学院大学天文与空间科学学院; 博洛尼亚大学物理与天文学系; 意大利国家天体物理研究所博洛尼亚空间科学与天体物理观测站; 意大利国家核物理研究所博洛尼亚分部; 中国科学院国家天文台射电天文与技术重点实验室; 北京师范大学物理学部; 清华大学天文系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究测量136个近邻星系的暗物质分布，发现中心区域暗物质密度低于ΛCDM模拟预期，且低密度区域随恒星质量增大而扩展，为未来模拟提供观测基准。
AI 中文摘要
流体动力学模拟中的重子反馈通常被用来缓解矮星系中的核-尖点问题。然而，重子过程也会引发暗物质的绝热收缩，导致大质量星系内部区域出现过于陡峭的密度轮廓和过高的暗物质比例。因此，跨越广泛恒星质量范围的星系暗物质分布是对此类模拟的关键检验，但此前一直缺乏全面的基准。在此，我们一致地测量了136个近邻星系从星系中心到20-50千秒差距半径范围内的暗物质分布，这些星系共同覆盖了恒星质量区间$10^9$-$10^{11.5}\\,M_{\odot}$内的局域质量-尺度关系。我们识别出中心区域暗物质密度低于$\Lambda$CDM模拟预期——随着恒星质量从$10^{10} M_{\odot}$增加到$10^{11.5} M_{\odot}$，该区域的尺度从约10千秒差距增长到$>50$千秒差距。尽管其物理起源尚不清楚，但这些低暗物质区域已被数据明确指示。我们的结果为未来探索替代暗物质模型和反馈过程的流体动力学模拟提供了重要的观测基准。
英文摘要
Baryonic feedback in hydrodynamical simulations is typically invoked to alleviate the core--cusp problem in dwarf galaxies. Yet baryonic processes also induce adiabatic contraction of dark matter, producing overly steep density profiles and excessively high dark matter fractions in the inner regions of massive galaxies. The dark matter distribution of galaxies across a wide stellar-mass range is therefore a critical test for such simulations, but a comprehensive benchmark has remained absent. Here, we consistently measure the dark matter distribution from galaxy centres out to radii of 20--50 kpc for 136 nearby galaxies that together span the local mass--size relation over the stellar mass interval $10^9$--$10^{11.5}\,M_{\odot}$. We identify central regions with lower dark matter densities relative to $Λ$CDM simulation expectations---whose extent grows from about 10 kpc to $>50$ kpc as stellar mass increases from $10^{10} M_{\odot}$ to $10^{11.5} M_{\odot}$. Although their physical origin remains unclear, these low--dark matter regions are clearly indicated by the data. Our results provide an important observational benchmark for future hydrodynamical simulations that explore alternative dark matter models and feedback processes.
Comments47 pages, 5 main figures, 9 Extended Data figures, and 1 Extended Data table. Accepted in principle by Nature Astronomy. This is the authors' manuscript version
