We study the properties of the dark matter component of the radially anisotropic stellar population recently identified in the Gaia data, using magneto-hydrodynamical simulations of Milky Way-like halos from the Auriga project. We identify 10 simulated galaxies that approximately match the rotation curve and stellar mass of the Milky Way. Four of these have an anisotropic stellar population reminiscent of the Gaia structure. We find an anti-correlation between the dark matter mass fraction of this population in the Solar neighbourhood and its orbital anisotropy. We estimate the local dark matter density and velocity distribution for halos with and without the anisotropic stellar population, and use them to simulate the signals expected in future xenon and germanium direct detection experiments. We find that a generalized Maxwellian distribution fits the dark matter halo integrals of the Milky Way-like halos containing the radially anisotropic stellar population. For dark matter particle masses below approximately 10 GeV, direct detection exclusion limits for the simulated halos with the anisotropic stellar population show a mild shift towards smaller masses compared to the commonly adopted Standard Halo Model.

中文翻译：

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盖亚径向各向异性子结构的暗物质成分

我们使用来自御夫座项目的类银河系光晕的磁流体动力学模拟，研究了最近在盖亚数据中发现的径向各向异性恒星群的暗物质成分的特性。我们确定了 10 个模拟星系，它们大致匹配银河系的旋转曲线和恒星质量。其中四个具有各向异性的恒星群，让人想起盖亚结构。我们发现太阳邻域中该种群的暗物质质量分数与其轨道各向异性之间存在反相关性。我们估计了有和没有各向异性恒星群的晕的局部暗物质密度和速度分布，并用它们来模拟未来氙和锗直接探测实验中预期的信号。我们发现广义麦克斯韦分布符合包含径向各向异性恒星群的类银河系晕的暗物质晕积分。对于低于大约 10 GeV 的暗物质粒子质量，与普遍采用的标准光晕模型相比，具有各向异性恒星群的模拟光晕的直接检测排除限显示出向更小质量的轻微转变。