论文标题
核星簇和核恒星盘的过渡区域中的恒星种群
Stellar Populations in the Transition Region of Nuclear Star Cluster and Nuclear Stellar Disc
论文作者
论文摘要
银河系核星簇（NSC）位于银河系中心的核恒星盘（NSD）内。尚未完全理解这两个组成部分的形成和演变以及它们如何相互影响。我们研究NSC和NSD过渡区域中的恒星种群。我们观察到两个$ \ sim $ 4.3 PC $^2 $ fields带有整体场光谱KMO（VLT），位于NSC的银河东部和西部的R $ \ sim $ 20 PC（> 4 r $ _e $）。我们提取和分析每个场> 200颗恒星的中分辨率恒星光谱。数据包含九个年轻的候选人。我们使用恒星光度法来估计年轻恒星的恒星肿块，有效温度和光谱类型。恒星与4-6岁的Myr一致，它们可能在五胞胎集群内形成，但分散在动态相互作用中。这两个田中的大多数恒星都是红色巨星，我们使用全光谱拟合测量它们的恒星金属度[m/h]。我们使用文献数据将我们的[M/H]分布与NSC和NSD进行比较，并发现整体金属性从中央NSC（在过渡区域）下降到NSD。从NSC到由NSD主导的区域的[M/H]的急剧减少表明，这两个组成部分具有不同的恒星种群和地层历史。
The Milky Way nuclear star cluster (NSC) is located within the nuclear stellar disc (NSD) in the Galactic centre. It is not fully understood if the formation and evolution of these two components are connected, and how they influence each other. We study the stellar populations in the transition region of NSC and NSD. We observed two $\sim$4.3 pc$^2$ fields with the integral-field spectrograph KMOS (VLT), located at r$\sim$20 pc (> 4 R$_e$) to the Galactic East and West of the NSC. We extract and analyse medium-resolution stellar spectra of >200 stars per field. The data contain in total nine young star candidates. We use stellar photometry to estimate the stellar masses, effective temperatures, and spectral types of the young stars. The stars are consistent with an age of 4-6 Myr, they may have formed inside the Quintuplet cluster, but were dispersed in dynamical interactions. Most stars in the two fields are red giant stars, and we measure their stellar metallicities [M/H] using full spectral fitting. We compare our [M/H] distributions to the NSC and NSD, using data from the literature, and find that the overall metallicity decreases from the central NSC, over the transition region, to the NSD. The steep decrease of [M/H] from the NSC to the region dominated by the NSD indicates that the two components have distinct stellar populations and formation histories.
