星系团内光的起源星系
The progenitor galaxies of the intracluster light
- Universidad de La Serena（拉塞雷纳大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究基于Illustris-TNG100模拟，探究z=0时星系团和星系群ICL的起源星系属性，发现ICL起源星系数量多于BCG，低质量及熄灭星系对ICL贡献更大，二者径向梯度受结构历史影响。
AI中文摘要：
星系团内光（ICL）是星系群和星系团的弥散恒星成分，受结构引力势束缚而非单个星系，主要由中等质量星系的剥离和并合形成，其形成与演化和星系群、星系团的中心星系（通常为星系团最亮星系BCG）密切相关。本研究旨在确定红移z=0时星系团和星系群ICL的起源星系属性，并将其与BCG的起源星系进行比较。我们从流体动力学Illustris-TNG100模拟中选取127个质量大于10^13 M⊙的星系团和星系群，通过在Holmberg半径处应用表面亮度阈值26.5 mag/arcsec^-2来分离ICL与BCG，将该半径内的恒星粒子定义为附着于BCG，半径外的则为ICL，随后确定ICL和BCG起源星系的质量及贡献。研究发现，ICL起源星系的数量随结构质量增加而增多，且ICL的起源星系数量多于BCG；ICL包含来自低质量星系的物质占比更大，熄灭星系贡献了ICL的很大一部分，且该占比随星系质量增大而升高；结构中外来物质的平均质量径向梯度对于ICL和BCG+ICL整体为负，且随结构质量增大而增大，表明来自更大质量起源星系的物质分布在星系团中心，该平均质量径向梯度受结构形成历史显著影响；ICL起源星系属性受结构历史影响，因此每个系统具有高度个体性，在给定结构质量下，形成ICL的起源星系属性存在多样性；尽管BCG与ICL共同演化，但BCG的起源星系数量更少、质量更大。
英文摘要：
Intracluster Light (ICL) is a diffuse stellar component of galaxy groups and clusters, bound to the structure's potential rather than to individual galaxies and primarily formed through the stripping and mergers of intermediate-mass galaxies. Its formation and evolution is strongly linked to the central galaxies of groups and clusters, typically the Brightest Cluster Galaxies (BCGs) in clusters. To determine the properties of the progenitor galaxies of the ICL of clusters and groups at redshift z = 0 and compare them with the progenitors of their BCGs. We select 127 clusters and groups in the hydrodynamic Illustris-TNG100 simulation above a mass of 10^{13}~$M_{\odot}$. We divide the ICL from the BCG by applying a surface brightness cut at the Holmberg radius of 26.5 mag/arcsec^{-2}, where star particles within this radius are defined as attached to the BCG, and outside, the ICL. We then determine the masses and contributions of progenitor galaxies of the ICL and BCG. We find that the number of ICL progenitors increases with structure mass, and that the ICL has more progenitors than the BCG. The ICL has a larger percentage of material from low-mass galaxies. Quenched galaxies contributed a large fraction of the ICL, and this fraction increases with galaxy mass. The mean mass radial gradient of ex-situ material in structures for the ICL and the BCG+ICL is generally negative and increases with structure mass, indicating that material from more massive progenitors is found towards the centres of clusters. The mean mass radial gradient is significantly impacted by structure formation history. ICL progenitor properties are impacted by structure history and are therefore highly individual to each system. At a given structure mass, there is diversity in the properties of the progenitors that formed the ICL. Although the BCG and the ICL co-evolve, the BCG has fewer, more massive progenitors.
