从流体动力学N体模拟探讨高密度环境中星系暗物质晕的截断
Probing the truncation of galaxy dark matter halos in high density environments from hydrodynamical N-body simulations
摘要：
我们分析了高分辨率，N体流体动力学模拟的基准星系团探测潮汐剥离的暗物质subhalos。这些模拟包括恒星形成的处方，使我们能够跟踪恒星组成部分的命运。我们研究了潮汐剥离对这些暗物质下晕中星系团的影响，作为星系团中心半径的函数。为了量化星系团的暗物质晕的程度，我们引入半质量半径r_half作为诊断参数，并研究了它与投影星系团中心距离R的演化关系.我们发现一个定义明确的趋势（r_half，R）：越接近星系团的中心，半质量半径越小。有趣的是，这一趋势在本研究中研究的所有红移框架中都可以推断出来，范围从z=0到z=0.7。在z=0时，星系团中心区域的星系晕被高度截断，最紧凑的半质量半径为10 kpc。我们还发现r_half依赖于光度，并给出了r_half与星系光度的标度关系。相应的星系团总质量也被发现随着投射的星系团中心距离和光度的增加而增加，但比（r_half，R）趋势更分散。比较星系团中恒星质量与总质量的分布，我们发现暗物质组分被优先剥离，而恒星组分仍然受到晕的保护，受潮汐力的影响要小得多。我们将这些结果与r_half的星系-星系透镜探测器进行了比较，并找到了定性的一致性。（节录）
英文摘要：
We analyze high resolution, N-body hydrodynamical simulations of fiducial galaxy clusters to probe tidal stripping of the dark matter subhalos. These simulations include a prescription for star formation allowing us to track the fate of the stellar component as well. We investigate the effect of tidal stripping on cluster galaxies hosted in these dark matter subhalos as a function of cluster-centric radius. To quantify the extent of the dark matter halos of cluster galaxies, we introduce the half mass radius r_half as a diagnostic, and study its evolution with projected cluster-centric distance R as a function of redshift. We find a well defined trend for (r_half,R): the closer the galaxies are to the center of the cluster, the smaller the half mass radius. Interestingly, this trend is inferred in all redshift frames examined in this work ranging from z=0 to z=0.7. At z=0, galaxy halos in the central regions of clusters are found to be highly truncated, with the most compact half mass radius of 10 kpc. We also find that r_half depends on luminosity and we present scaling relations of r_half with galaxy luminosity. The corresponding total mass of the cluster galaxies is also found to increase with projected cluster-centric distance and luminosity, but with more scatter than the (r_half,R) trend. Comparing the distribution of stellar mass to total mass for cluster galaxies, we find that the dark matter component is preferentially stripped, whereas the stellar component remains protected by the halo and is much less affected by tidal forces. We compare these results with galaxy-galaxy lensing probes of r_half and find qualitative agreement. (Abridged)
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