星团作为大麦哲伦云扰动南外盘的示踪体
Star clusters as tracers of the perturbed southern outer disk of the Large Magellanic Cloud
- Instituto Interdisciplinario de Ciencias Básicas (ICB), CONICET-UNCuyo（基础科学跨研究所（ICB），阿根廷国家科学研究委员会-门多萨国立大学）
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（阿根廷国家科学研究委员会）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
本研究利用70个星团示踪大麦哲伦云南外盘，发现其受小麦哲伦云潮汐扰动形成波纹状结构，但化学上仍属大麦哲伦云。
中文摘要 AI 辅助
大麦哲伦云和小麦哲伦云（L/SMC）之间复杂的相互作用历史在其结构和化学演化上留下了显著印记。在本工作中，我们利用位于大麦哲伦云南外盘（$R > 5^{\circ}$）的70个星团样本，来示踪这些潮汐扰动的幅度。利用SMASH DR2巡天的深$g,i$测光数据以及自动星团分析（ASTeCA）代码，我们提供了星团年龄、金属丰度和日心距离的同质化测定。我们的结果显示，该星团群体的年龄范围在1.02至3.34 Gyr之间，金属丰度介于-0.70至-0.07 dex之间。我们发现，日心距离较大的星团主要位于面向小麦哲伦云的西部区域。垂直分布分析揭示了相对于大麦哲伦云中平面的平均高度（$\langle Z \rangle$）存在振荡变化，并且朝向西方内禀垂直弥散（$W$）有所增加。这些几何特征与近期与小麦哲伦云潮汐相遇所诱导的波纹状盘结构一致。在化学上，这些星团遵循大麦哲伦云典型的年龄-金属丰度关系，并能很好地由爆发型形成模型所表征。缺乏化学性质独特的星团表明，虽然相互作用足以动态地使外盘变形并产生波纹，但并未导致从小麦哲伦云显著捕获星团。我们得出结论，南外盘在结构和化学上仍属于大麦哲伦云的一部分，尽管其受到潮汐力的强烈扰动。
英文摘要
The complex interaction history between the Large and Small Magellanic Clouds (L/SMC) has left significant imprints on their structural and chemical evolution. In this work, we use a sample of 70 star clusters located in the southern outer disk of the LMC ($R > 5^{\circ}$) to trace the magnitude of these tidal perturbations. Using deep $g,i$ photometry from the SMASH DR2 survey and the Automated Stellar Cluster Analysis (ASTeCA) code, we provide a homogeneous determination of cluster ages, metallicities, and heliocentric distances. Our results show a population with ages ranging from 1.02 to 3.34 Gyr and metallicities between -0.70 and -0.07 dex. We find that clusters at greater heliocentric distances are predominantly located toward the western regions, facing the SMC. Analysis of the vertical distribution reveals an oscillatory variation in the mean height ($\langle Z \rangle$) relative to the LMC mid-plane and an increase in intrinsic vertical dispersion ($W$) toward the West. These geometric features are consistent with a corrugated disk structure induced by recent tidal encounters with the SMC. Chemically, the clusters follow the age-metallicity relationship typical of the LMC and are well-represented by a bursting-type formation model. The lack of chemically distinct clusters suggests that while the interaction was sufficient to dynamically deform and corrugate the outer disk, it did not lead to significant cluster capture from the SMC. We conclude that the southern outer disk remains structurally and chemically part of the LMC, despite being heavily perturbed by tidal forces.
