Substructures in hydrodynamical cluster simulations
Substructures in hydrodynamical cluster simulations
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DOI：
10.1111/j.1365-2966.2009.15034.x
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发表时间：
2008-08
影响因子：
4.8
通讯作者：
K. Dolag;S. Borgani;S. Borgani;S. Borgani;G. Murante;V. Springel
中科院分区：
文献类型：
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作者：
K. Dolag;S. Borgani;S. Borgani;S. Borgani;G. Murante;V. Springel
暗物质亚晕的丰度和结构在最近的暗物质模拟研究中得到了广泛的分析，但对重子物理学对晕子结构的影响知之甚少。在这里，我们扩展子结构识别的SUBFIND算法，使它可以可靠地应用到耗散流体动力学模拟，包括星星的形成。特别是，这可以在星系团模拟中将星系识别为子结构，并确定其重力束缚恒星、暗物质和冷热气体的含量。使用大量的宇宙学集群模拟，我们提出了一个详细的分析晕子结构的星系团的流体动力学模拟，特别是集中在辐射和非辐射气体物理和非标准物理，如热传导和反馈的星系外流的影响。我们还研究了数值滋扰参数，如人工粘度参数化的影响。我们发现，扩散热气体有效地剥离从subhaloes时，他们进入高压集群大气。这具有相对于相应的仅暗物质模拟降低次晕质量函数的效果。这些影响在辐射运行中得到缓解，重子在中心的次晕区域凝聚并形成紧凑的恒星核心。然而，在所有的情况下，只有一个非常小的部分，百分之一的顺序，在集群维里半径内的subhaloes保存引力约束的热气体大气。在subhaloes的气体所贡献的质量分数被发现与集群中心的距离增加。有趣的是，这种趋势远远超出了维里半径，从而表明星系在相当长的距离内感受到加压星系团气体的环境。致密的恒星核心（即星系）通常比纯暗物质的暗晕更能抵抗潮汐的破坏。尽管如此，在我们模拟的星系团中以恒星为主的子结构的比例只有~ 10%.We预计，在我们的模拟有限的分辨率使星系过于容易受到潮汐破坏，因此上述以恒星为主的星系的比例应该代表一个下限的实际比例的星系幸存的破坏其主机暗物质subhalo。
The abundance and structure of dark matter subhaloes have been analysed extensively in recent studies of dark-matter-only simulations, but comparatively little is known about the impact of baryonic physics on halo substructures. We here extend the SUBFIND algorithm for substructure identification such that it can be reliably applied to dissipative hydrodynamical simulations that include star formation. This allows, in particular, the identification of galaxies as substructures in simulations of clusters of galaxies and a determination of their content of gravitationally bound stars, dark matter and hot and cold gas. Using a large set of cosmological cluster simulations, we present a detailed analysis of halo substructures in hydrodynamical simulations of galaxy clusters, focusing in particular on the influence both of radiative and non-radiative gas physics and of non-standard physics such as thermal conduction and feedback by galactic outflows. We also examine the impact of numerical nuisance parameters such as artificial viscosity parameterizations. We find that diffuse hot gas is efficiently stripped from subhaloes when they enter the highly pressurized cluster atmosphere. This has the effect of decreasing the subhalo mass function relative to a corresponding dark-matter-only simulation. These effects are mitigated in radiative runs, where baryons condense in the central subhalo regions and form compact stellar cores. However, in all cases, only a very small fraction, of the order of one per cent, of subhaloes within the cluster virial radii preserve a gravitationally bound hot gaseous atmosphere. The fraction of mass contributed by gas in subhaloes is found to increase with the cluster-centric distance. Interestingly, this trend extends well beyond the virial radii, thus showing that galaxies feel the environment of the pressurized cluster gas over fairly large distances. The compact stellar cores (i.e. galaxies) are generally more resistant against tidal disruption than pure dark matter subhaloes. Still, the fraction of star-dominated substructures within our simulated clusters is only ~10 per cent. We expect that the finite resolution in our simulations makes the galaxies overly susceptible to tidal disruption, hence the above fraction of star-dominated galaxies should represent a lower limit for the actual fraction of galaxies surviving the disruption of their host dark matter subhalo.