ZOMG - III. The effect of halo assembly on the satellite population
ZOMG - III. The effect of halo assembly on the satellite population
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DOI：
10.1093/mnras/stx2489
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发表时间：
2017-07
影响因子：
4.8
通讯作者：
E. Garaldi;E. Romano-D'iaz;M. Borzyszkowski;C. Porciani
中科院分区：
文献类型：
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作者：
E. Garaldi;E. Romano-D'iaz;M. Borzyszkowski;C. Porciani
我们使用变焦流体动力学模拟研究星系大小的暗物质晕与不同的组装历史的卫星的属性。我们考虑两类晕在红移z=0：'停滞'晕，在z>1$和'吸积'的，今天仍然形成。以前，我们表明，停滞的晕嵌入在宇宙网的厚丝中，而吸积的晕位于多个细丝汇聚的地方。我们发现这两类卫星既有相似的性质，也有不同的性质。它们的质量谱、径向计数剖面、重子和恒星含量以及它们脱落的物质数量都无法区分。然而，锁定在卫星的质量分数是大得多的吸积晕，因为他们经历了更多的合并在后期。最大的差异是在卫星运动学。子结构下降对吸积晕沿着准径向轨迹，而一个重要的切向速度分量的开发，吸积前，而围绕停滞晕的灯丝轨道。因此，速度各向异性参数的卫星（$\beta$）是积极的吸积晕和消极的停滞。这个特征使我们能够根据最近的测量结果$\beta$暂时将银河系晕归类为停滞。我们的晕中有一半包含卫星群，它们的轨道角动量对齐，对应于太空中的扁平结构。这些特征不是由重子物理学驱动的，只在拥有宏伟设计的螺旋星系的晕中发现，与它们的组装历史无关。
We use zoom hydrodynamical simulations to investigate the properties of satellites within galaxy-sized dark-matter haloes with different assembly histories. We consider two classes of haloes at redshift $z=0$: `stalled' haloes that assembled at $z>1$ and `accreting' ones that are still forming nowadays. Previously, we showed that the stalled haloes are embedded within thick filaments of the cosmic web while the accreting ones lie where multiple thin filaments converge. We find that satellites in the two classes have both similar and different properties. Their mass spectra, radial count profiles, baryonic and stellar content, and the amount of material they shed are indistinguishable. However, the mass fraction locked in satellites is substantially larger for the accreting haloes as they experience more mergers at late times. The largest difference is found in the satellite kinematics. Substructures fall towards the accreting haloes along quasi-radial trajectories whereas an important tangential velocity component is developed, before accretion, while orbiting the filament that surrounds the stalled haloes. Thus, the velocity anisotropy parameter of the satellites ($\beta$) is positive for the accreting haloes and negative for the stalled ones. This signature enables us to tentatively categorize the Milky Way halo as stalled based on a recent measurement of $\beta$. Half of our haloes contain clusters of satellites with aligned orbital angular momenta corresponding to flattened structures in space. These features are not driven by baryonic physics and are only found in haloes hosting grand-design spiral galaxies, independently of their assembly history.