It is yet to be understood how large-scale environments influence star formation activity in galaxy clusters. One recently proposed mechanism is that galaxy clusters can remain star forming when fed by infalling groups and star-forming galaxies from large-scale structures (LSSs) surrounding them (the “web-feeding” model). Using the COSMOS2020 catalog that has half a million galaxies with high-accuracy (σΔz/1+z ∼ 0.01) photometric redshifts, we study the relationship between star formation activities in galaxy clusters and their surrounding environment to test the web-feeding model. We first identify 68 cluster candidates at 0.3 ≤ z ≤ 1.4 with halo masses at 1013.0–1014.5M⊙ and the surrounding LSSs with the friends-of-friends algorithm. We find that clusters with low fractions of quiescent galaxies tend to be connected with extended LSSs as expected in the web-feeding model. We also investigated the time evolution of the web-feeding trend using the IllustrisTNG cosmological simulation. Even though no clear correlation between the quiescent galaxy fraction of galaxy clusters and the significance of LSSs around them is found in the simulation, we verify that the quiescent galaxy fractions of infallers such as groups (M200 ≥ 1012M⊙) and galaxies (M200 < 1012M⊙) are smaller than the quiescent fraction of cluster members and that infallers can lower the quiescent fraction of clusters. These results imply that cluster-to-cluster variations of quiescent galaxy fraction at z ≤ 1 can at least partially be explained by feeding materials through cosmic webs to clusters.

中文翻译：

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COSMOS 场星系团中恒星形成的宇宙网馈模型测试


大尺度环境如何影响星系团中的恒星形成活动尚不清楚。最近提出的一种机制是，当星系团被来自它们周围的大尺度结构 （LSS） 的下落群和恒星形成星系喂养时，星系团可以保持恒星形成（“网馈”模型）。使用包含五十万个具有高精度 （σΔz/1+z ∼ 0.01） 光度红移的星系的 COSMOS2020 星表，我们研究了星系团中恒星形成活动与其周围环境之间的关系，以测试网络馈送模型。我们首先在 0.3 ≤z ≤ 1.4 处确定了 68 个光晕质量在 1013.0-1014.5M 处的候选星团⊙以及周围的 LSS。我们发现，正如网络馈送模型中所预期的那样，静止星系分数低的星系团往往与扩展的 LSS 相连。我们还使用 IllustrisTNG 宇宙学模拟研究了 Web 馈送趋势的时间演变。尽管在模拟中没有发现星系团的静止星系分数与其周围LSS的显著性之间的明确相关性，但我们验证了诸如星系群（M200 ≥ 1012M⊙）和星系（M200 < 1012M⊙）等插入体的静止星系分数小于星系团成员的静止分数，并且插入体可以降低星系团的静止分数。这些结果表明，z ≤ 1 处静止星系分数的星系团间变化至少可以部分地解释为通过宇宙网将物质输送到星系团中。