Under the FIRElight: Stellar Tracers of the Local Dark Matter Velocity Distribution in the Milky Way
Under the FIRElight: Stellar Tracers of the Local Dark Matter Velocity Distribution in the Milky Way
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DOI：
10.3847/1538-4357/ab3afc
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发表时间：
2018-10
期刊：
影响因子：
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通讯作者：
L. Necib;M. Lisanti;S. Garrison-Kimmel;A. Wetzel;R. Sanderson;P. Hopkins;C. Faucher-Giguère;D. Ke
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文献类型：
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作者：
L. Necib;M. Lisanti;S. Garrison-Kimmel;A. Wetzel;R. Sanderson;P. Hopkins;C. Faucher-Giguère;D. Ke
盖亚时代为发现太阳附近被破坏的卫星星系的残余物开辟了新的可能性。如果本地吸积恒星的人口与暗物质来源于相同的合并，然后可以直接映射暗物质分布。使用两个宇宙学放大的银河系质量星系的流体动力学模拟从Latte套件的火-2模拟，我们发现恒星和暗物质的速度分布之间的强相关性，在太阳圈的吸积从发光的卫星。这种对应关系适用于暗物质，无论是放松或在一个运动学子结构称为泥石流，是一致的两个模拟主机与不同的合并历史。由于暗物质和恒星之间可能存在空间偏移，因此对于流来说，这种对应关系更成问题。我们演示了如何重建暗物质的速度分布从所观察到的吸积恒星人口的属性，通过适当占个别合并贡献的恒星暗物质的比例。这一过程并没有考虑到来自非发光卫星的暗物质，这些暗物质可能构成了局部贡献的一个重要部分。在使用Fire-2模拟验证此方法后，我们将其应用于银河系，并使用它来恢复与最近发现的太阳附近的恒星碎片场相关的暗物质速度分布。基于盖亚的结果，我们估计，当地的暗物质是吸积发光合并是在泥石流。
The Gaia era opens new possibilities for discovering the remnants of disrupted satellite galaxies in the solar neighborhood. If the population of local accreted stars is correlated with the dark matter sourced by the same mergers, one can then map the dark matter distribution directly. Using two cosmological zoom-in hydrodynamic simulations of Milky-Way-mass galaxies from the Latte suite of the Fire-2 simulations, we find a strong correlation between the velocity distribution of stars and dark matter at the solar circle that were accreted from luminous satellites. This correspondence holds for dark matter that is either relaxed or in a kinematic substructure called debris flow, and is consistent between two simulated hosts with different merger histories. The correspondence is more problematic for streams because of possible spatial offsets between the dark matter and stars. We demonstrate how to reconstruct the dark matter velocity distribution from the observed properties of the accreted stellar population by properly accounting for the ratio of stars to dark matter contributed by individual mergers. This procedure does not account for the dark matter that originates from nonluminous satellites, which may constitute a nontrivial fraction of the local contribution. After validating this method using the Fire-2 simulations, we apply it to the Milky Way and use it to recover the dark matter velocity distribution associated with the recently discovered stellar debris field in the solar neighborhood. Based on results from Gaia, we estimate that of the local dark matter that is accreted from luminous mergers is in debris flow.