标题： 激进耗散暗矮星：原子暗物质对孤立矮星系内部密度的影响 显示英文标题

标题： Aggressively-Dissipative Dark Dwarfs: The Effects of Atomic Dark Matter on the Inner Densities of Isolated Dwarf Galaxies

摘要： 我们展示了针对由冷暗物质和强耗散子成分组成的暗区的第一套宇宙学流体动力学聚焦模拟。 这些模拟在GIZMO中实现，并包括遵循FIRE-2星系形成物理模型的标准重子物质。 耗散暗物质被建模为原子暗物质(aDM)，它形成一种暗氢气，其冷却方式直接类比于标准模型。 我们的模拟套件包括七种不同的$\sim 10^{10} M_{\odot}$系统模拟，这些模拟在aDM微观物理和矮星系的演化历史上有所不同。 我们确定了一个aDM参数空间区域，其中冷却率很高， resulting晕密度分布是普遍的。 在这个区域内，aDM气体在高红移迅速冷却，只有很小一部分以中心暗气体盘的形式存活；大部分则集中坍缩成非碰撞的暗“团块”，这些是次分辨率暗致密物体的聚集体。 这些暗团块在星系内部迅速达到平衡，产生一个近似等温分布，可以用一个简单的拟合函数来建模。 即使只有很小一部分($\sim 5\%$)的总暗物质是强耗散的，经典矮星系的中心密度也可以提高一个数量级以上，为观测提供了明确的预测。 显示英文摘要

摘要： We present the first suite of cosmological hydrodynamical zoom-in simulations of isolated dwarf galaxies for a dark sector that consists of Cold Dark Matter and a strongly-dissipative sub-component. The simulations are implemented in GIZMO and include standard baryons following the FIRE-2 galaxy formation physics model. The dissipative dark matter is modeled as Atomic Dark Matter (aDM), which forms a dark hydrogen gas that cools in direct analogy to the Standard Model. Our suite includes seven different simulations of $\sim 10^{10} M_{\odot}$ systems that vary over the aDM microphysics and the dwarf's evolutionary history. We identify a region of aDM parameter space where the cooling rate is aggressive and the resulting halo density profile is universal. In this regime, the aDM gas cools rapidly at high redshifts and only a small fraction survives in the form of a central dark gas disk; the majority collapses centrally into collisionless dark "clumps", which are clusters of sub-resolution dark compact objects. These dark clumps rapidly equilibrate in the inner galaxy, resulting in an approximately isothermal distribution that can be modeled with a simple fitting function. Even when only a small fraction ($\sim 5\%$) of the total dark matter is strongly dissipative, the central densities of classical dwarf galaxies can be enhanced by over an order of magnitude, providing a sharp prediction for observations.