论文标题
运动学数据将核星簇重建为银河系中最富含金属的区域
Kinematic data rebuild the Nuclear star cluster as the most metal rich region of the Galaxy
论文作者
论文摘要
银河中心（GC）位于距地球仅8 kpc的位置，构成了一个独特的模板来理解银河核。然而，对GC的高拥挤和灭绝的障碍者对其主要恒星组成部分，核恒星盘（NSD）和核星团（NSC）（NSC）的研究。最近的工作表明，可以通过恒星的不同灭绝来区分NSD和NSC，沿着视线向NSC区分开。这促使我们分析了不同灭绝组的适当运动，径向速度和金属性分布。我们使用光度法，运动学和金属性数据来区分以NSC以NSC为中心的区域中可能的NSD和NSC恒星。我们与NSD和NSC的预期运动学一致，检测到了两个不同的恒星灭绝组，并为每个恒星获得了明显不同的适当运动分布。我们得出了对于NSD和NSC似乎不同的径向速度图。我们还发现了每个组件的不同金属度，其中最大的金属性是针对最熄灭的恒星测量的。我们获得了每个灭绝组的金属性分布最好通过双峰分布拟合，表明每个灭绝分布都存在两个金属性成分（一个略低于太阳金属性的宽度，一个较高的金属较窄的较窄一个，这对于高灭绝恒星来说是最大的）。我们得出的结论是，两个灭绝组都是具有不同运动学和金属性的不同GC成分，并且与NSD和NSC相对应。因此，可以通过不同的灭绝来区分它们。高平均金属性，$ [m/h] \ sim0.3 $ \ dex，为NSC金属富含恒星获得，支持NSC是银河系中最富含金属的富含金属的区域。
The Galactic centre (GC) is located at only 8 kpc from Earth and constitutes a unique template to understand Galactic nuclei. Nevertheless, the high crowding and extinction towards the GC hamper the study of its main stellar components, the nuclear stellar disc (NSD) and the nuclear star cluster (NSC). Recent work has suggested that the NSD and the NSC can be distinguished along the line of sight towards the NSC via the different extinction of their stars. This motivated us to analyse the proper motion, radial velocity, and the metallicity distributions of the different extinction groups. We use photometric, kinematic, and metallicity data to distinguish between probable NSD and NSC stars in a region centred on the NSC. We detected two different extinction groups of stars and obtained significantly different proper motion distributions for each of them, in agreement with the expected kinematics for the NSD and the NSC. We derived radial velocity maps that appear to be different for the NSD and the NSC. We also found different metallicities for each of the components, with the largest one measured for the most extinguished group of stars. We obtained that the metallicity distribution of each extinction group is best fitted by a bimodal distribution, indicating the presence of two metallicity components for each of them (a broad one slightly below solar metallicity, and a more metal rich narrower one, that is largest for the high extinction group of stars). We conclude that both extinction groups are distinct GC components with different kinematics and metallicity, and correspond to the NSD and the NSC. Therefore, it is possible to distinguish them via their different extinction. The high mean metallicity, $[M/H]\sim0.3$\,dex, obtained for the NSC metal rich stars, supports that the NSC is arguabily the most metal rich region of the Galaxy.
