标题： 超 faint矮星系中的恒星分布表明偏离了无碰撞冷暗物质范式 显示英文标题

标题： The stellar distribution in ultra-faint dwarf galaxies suggests deviations from the collision-less cold dark matter paradigm

摘要： 揭开暗物质（DM）的本质是现代物理学的主要目标之一。 这里我们提供了证据，表明其与无碰撞冷暗物质（CDM）范式的偏差。 这源于使用哈勃太空望远镜（HST）测量的六个超微矮星系（UFD）中恒星的径向分布。 在尺寸和中心密度经过微不足道的重新归一化后，这六个UFD显示出相同的恒星分布，这种分布恰好具有一个中央平台或核心。 假设球对称性和各向同性速度，Eddington反演法证明了观测到的分布与CDM粒子特征势不一致。 在这些假设下，观测到的恒星分布内核斜率排除了UFD存在于CDM势中的可能性，置信水平超过97%。 这些星系极低的恒星质量（10**3-10**4 Msun），阻止了恒星反馈修改CDM势的形状。 对于观测到的核心的其他可能解释，如偏离球对称性和各向同性、潮汐力以及所用CDM势的具体形式，在模拟和/或观测中都不被支持。 因此，证据表明，暗物质粒子之间的碰撞或其他CDM替代方案可能正在塑造这些星系。 许多这些替代方案产生的核心引力势，与观测到的恒星分布一致。 显示英文摘要

摘要： Unraveling the nature of dark matter (DM) stands as a primary objective in modern physics. Here we present evidence suggesting deviations from the collisionless Cold DM (CDM) paradigm. It arises from the radial distribution of stars in six Ultra Faint Dwarf (UFD) galaxies measured with the Hubble Space Telescope (HST). After a trivial renormalization in size and central density, the six UFDs show the same stellar distribution, which happens to have a central plateau or core. Assuming spherical symmetry and isotropic velocities, the Eddington inversion method proves the observed distribution to be inconsistent with potentials characteristic of CDM particles. Under such assumptions, the observed innermost slope of the stellar profile discards the UFDs to reside in a CDM potential at a > 97% confidence level. The extremely low stellar mass of these galaxies, 10**3-10**4 Msun , prevents stellar feedback from modifying the shape of a CDM potential. Other conceivable explanations for the observed cores, like deviations from spherical symmetry and isotropy, tidal forces, and the exact form of the used CDM potential, are disfavored by simulations and/or observations. Thus, the evidence suggests that collisions among DM particles or other alternatives to CDM are likely shaping these galaxies. Many of these alternatives produce cored gravitational potentials, shown here to be consistent with the observed stellar distribution.