Dwarf galaxies in CDM, WDM, and SIDM: disentangling baryons and dark matter physics
Dwarf galaxies in CDM, WDM, and SIDM: disentangling baryons and dark matter physics
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DOI：
10.1093/mnras/stz2613
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发表时间：
2018-11
影响因子：
4.8
通讯作者：
Alex Fitts;M. Boylan-Kolchin;Brandon Bozek;J. Bullock;A. Graus;V. Robles;P. Hopkins;K. El-Badry;S. Garrison-Kimmel;C. Faucher-Giguère;A. Wetzel;D. Keres̆
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文献类型：
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作者：
Alex Fitts;M. Boylan-Kolchin;Brandon Bozek;J. Bullock;A. Graus;V. Robles;P. Hopkins;K. El-Badry;S. Garrison-Kimmel;C. Faucher-Giguère;A. Wetzel;D. Keres̆
我们提出了一套FIRE-2宇宙学放大模拟孤立场矮星系，所有的质量为$M_{\rm晕} \approximately 10^{10}\，{\rm M}_{\odot }$在z = 0，在一系列的暗物质模型。对于第一次，我们比较了自相互作用暗物质（SIDM）和/或暖暗物质（WDM）模型如何影响组装的历史，以及在完全流体动力学模拟的矮星的中心密度结构。具有较小恒星半质量半径（r1/2 < 500 pc）的矮星具有较低的σ σ/Vmax比，强化了较小的矮星可能存在于比天真预期更大的晕中的想法。大多数用自相互作用模拟的矮星实际上经历了它们内部密度轮廓的收缩，相对于只产生暗物质的运行中产生的核心，增加了重子，尽管模拟的矮星的中心密度总是低于ΛCDM。所有模拟中的V1/2-r1/2关系通常与局部场矮星的观测结果一致，尽管像杜鹃这样的紧凑天体提供了一个独特的挑战。总的来说，包含重子大大减少了暗物质物理学在矮星系可观测特性中的任何明显特征。小矮星中心区域（<400 pc）的空间分辨旋转曲线可以提供一种区分CDM、WDM和SIDM的方法，然而：在这个模拟套件中探测的质量下，具有小r1/2值的矮星的核心密度分布只能来自暗物质的自相互作用。
We present a suite of FIRE-2 cosmological zoom-in simulations of isolated field dwarf galaxies, all with masses of $M_{\rm halo} \approx 10^{10}\, {\rm M}_{\odot }$ at z = 0, across a range of dark matter models. For the first time, we compare how both self-interacting dark matter (SIDM) and/or warm dark matter (WDM) models affect the assembly histories as well as the central density structure in fully hydrodynamical simulations of dwarfs. Dwarfs with smaller stellar half-mass radii (r1/2 < 500 pc) have lower σ⋆/Vmax ratios, reinforcing the idea that smaller dwarfs may reside in haloes that are more massive than is naively expected. The majority of dwarfs simulated with self-interactions actually experience contraction of their inner density profiles with the addition of baryons relative to the cores produced in dark-matter-only runs, though the simulated dwarfs are always less centrally dense than in ΛCDM. The V1/2–r1/2 relation across all simulations is generally consistent with observations of Local Field dwarfs, though compact objects such as Tucana provide a unique challenge. Overall, the inclusion of baryons substantially reduces any distinct signatures of dark matter physics in the observable properties of dwarf galaxies. Spatially resolved rotation curves in the central regions (<400 pc) of small dwarfs could provide a way to distinguish between CDM, WDM, and SIDM, however: at the masses probed in this simulation suite, cored density profiles in dwarfs with small r1/2 values can only originate from dark matter self-interactions.