Empirical Determination of Dark Matter Velocities Using Metal-Poor Stars.
Empirical Determination of Dark Matter Velocities Using Metal-Poor Stars.
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DOI：
10.1103/physrevlett.120.041102
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发表时间：
2017-04
影响因子：
8.6
通讯作者：
Jonah Herzog-Arbeitman;M. Lisanti;P. Madau;L. Necib
中科院分区：
文献类型：
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作者：
Jonah Herzog-Arbeitman;M. Lisanti;P. Madau;L. Necib
银河系的暗物质晕是由较小的亚晕聚集形成的。这些亚单元也包含着恒星——通常是年老的和缺乏金属的——它们是由分裂事件沉积在银河系内部区域的。在这封信中，我们展示了太阳附近的暗物质和金属贫乏的恒星由于它们共同的起源而具有相似的运动学。利用高分辨率的eris模拟，在一个真实的银河系模拟星系中追踪暗物质和重子的演化，我们证明了金属贫乏的恒星确实是局部、虚拟化的暗物质速度分布的有效示踪剂。因此，当地暗物质的速度可以从斯隆数字巡天在距离太阳4kpc范围内对恒星晕的观测中推断出来。这种经验分布在许多重要方面与标准晕模型不同，并表明对于低于10 GeV的暗物质质量，自旋无关散射截面的边界可能会减弱。来自盖亚的数据将使我们能够进一步完善光滑暗物质成分的预期分布，并测试局部亚结构的存在。
The Milky Way dark matter halo is formed from the accretion of smaller subhalos. These sub-units also harbor stars-typically old and metal-poor-that are deposited in the Galactic inner regions by disruption events. In this Letter, we show that the dark matter and metal-poor stars in the Solar neighborhood share similar kinematics due to their common origin. Using the high-resolution eris simulation, which traces the evolution of both the dark matter and baryons in a realistic Milky Way analog galaxy, we demonstrate that metal-poor stars are indeed effective tracers for the local, virialized dark matter velocity distribution. The local dark matter velocities can therefore be inferred from observations of the stellar halo made by the Sloan Digital Sky Survey within 4 kpc of the Sun. This empirical distribution differs from the standard halo model in important ways and suggests that the bounds on the spin-independent scattering cross section may be weakened for dark matter masses below ∼10 GeV. Data from Gaia will allow us to further refine the expected distribution for the smooth dark matter component, and to test for the presence of local substructure.