Using cosmological hydrodynamical zoom-in simulations, we explore the properties of subhalos in Milky Way analogs that contain a subcomponent of atomic dark matter (ADM). ADM differs from cold dark matter (CDM) due to the presence of self-interactions that lead to energy dissipation, analogous to standard model baryons. This model can arise in dark sectors that are natural and theoretically motivated extensions to the standard model. The simulations used in this work were carried out using GIZMO and utilize the FIRE-2 galaxy formation physics in the standard model baryonic sector. For the parameter points we consider, the ADM gas cools efficiently, allowing it to collapse to the center of subhalos. This increases a subhalo’s central density and affects its orbit, with more subhalos surviving small pericentric passages. The subset of subhalos that host satellite galaxies have cuspier density profiles and smaller stellar half-mass radii relative to CDM. The entire population of dwarf galaxies produced in the ADM simulations is more compact than those seen in CDM simulations, unable to reproduce the entire diversity of observed dwarf galaxy structures. Additionally, we also identify a population of highly compact subhalos that consist nearly entirely of ADM and form in the central region of the host, where they can leave distinctive imprints in the baryonic disk. This work presents the first detailed exploration of subhalo properties in a strongly dissipative dark matter scenario, providing intuition for how other regions of ADM parameter space, as well as other dark sector models, would impact galactic-scale observables.

中文翻译：

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耗散暗子结构：原子暗物质对银河系模拟子晕的影响


使用宇宙流体动力学放大模拟，我们探索了包含原子暗物质（ADM）子成分的银河系类似物中子晕的特性。 ADM 与冷暗物质 (CDM) 不同，因为存在导致能量耗散的自相互作用，类似于标准模型重子。该模型可以出现在暗区中，这是标准模型的自然和理论上的扩展。这项工作中使用的模拟是使用 GIZMO 进行的，并利用标准模型重子扇区中的 FIRE-2 星系形成物理学。对于我们考虑的参数点，ADM 气体有效冷却，使其塌陷到子晕中心。这增加了子晕的中心密度并影响其轨道，更多的子晕在中心周围的小通道中幸存下来。与 CDM 相比，卫星星系所在的子晕子集具有尖峰密度分布和更小的恒星半质量半径。 ADM 模拟中产生的整个矮星系群比 CDM 模拟中看到的更紧凑，无法重现观测到的矮星系结构的全部多样性。此外，我们还发现了一群高度致密的子晕，它们几乎完全由 ADM 组成，形成于宿主的中心区域，在那里它们可以在重子盘上留下独特的印记。这项工作首次对强耗散暗物质场景中的子晕特性进行了详细探索，为 ADM 参数空间的其他区域以及其他暗区模型如何影响银河尺度的可观测提供了直觉。