论文标题
核星簇的近红外光谱：在冰山一角下方查看和与外乳外核的比较
The Near-Infrared Spectrum of the Nuclear Star Cluster: Looking Below the Tip of the Iceberg and Comparisons with Extragalactic Nuclei
论文作者
论文摘要
讨论了银河核星簇（NSC）的长片近红外（NIR）光谱。光谱将NSC的主要轴置于其半径半径。 NAI2.21UM和CAI2.26UM的等效宽度在NSC中心外部，那里的核凸起恒星的光对总通量贡献了很大一部分，与太阳能化学混合物一致。相反，即使在去除了最亮的恒星中的光之后，NAI2.21UM和NAI2.21UM和CAI2.26UM的等效宽度也比具有太阳化学混合物的模型所预期的要大。 NAI2.21UM和CAI2.26UM比在一系列进化状态的太阳化学混合物所预测的要深，与以前的研究相一致，这些研究发现NSC在NSC中心附近的大多数恒星是由具有非微光化学混合物的材料形成的。还提取了一系列的nebular发射和GC附近最年轻的恒星。提取的NIR光谱中排放特征的等效宽度与NGC 253核谱中的发射特征相似，因此认为，如果NSC中心附近的恒星形成的当前情节一直在进行至少几点MYR。
Long-slit near-infrared (NIR) spectra of the Galactic nuclear star cluster (NSC) are discussed. The spectra sample the major axis of the NSC out to its half light radius. The equivalent widths of NaI2.21um and CaI2.26um outside of the center of the NSC, where light from nuclear bulge stars contributes a large fraction to the total flux, are consistent with solar chemical mixtures. In contrast, the equivalent widths of NaI2.21um and CaI2.26um near the center of the NSC are larger than expected from models with solar chemical mixtures, even after light from the brightest evolved stars is removed. That NaI2.21um and CaI2.26um are deeper than predicted for solar chemical mixtures over a range of evolutionary states is consistent with previous studies that find that the majority of stars near the center of the NSC formed from material that had non-solar chemical mixtures. A spectrum of nebular emission and the youngest stars near the GC is also extracted. The equivalent widths of emission features in the extracted NIR spectrum are similar to those in the nuclear spectrum of NGC 253, and it is argued that this agreement is best achieved if the current episode of star formation near the center of the NSC has been in progress for at least a few Myr.
