论文标题
lamost的两部分射手座流对南部银河帽的指向区域的完整光谱调查
Two Portions of Sagittarius Stream in the LAMOST Complete Spectroscopic Survey of Pointing Area at Southern Galactic Cap
论文作者
论文摘要
We constructed a sample of 13,798 stars with $T\rm_{eff}$, log $g$, [Fe/H], radial velocity, proper motions and parallaxes from LAMOST DR5 and Gaia DR2 in the LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) at the Southern Galactic Cap consisting of areas A and B. Using the distributions in both proper motions and radial velocity, we在这两个方面发现了非常重要的过度繁殖。这些子结构很可能是Sagittarius（SGR）流的一部分。使用噪声（DBSCAN）算法的应用程序的密度空间聚类，确定了220个候选式流。根据与太阳和发布模型的距离，其中106个恒星可能是SGR流的成员。这些成员使用Xiang等人的[$α$/fe]的丰度模式。被发现类似于[Fe/H] $ <$ -1.5的银河田间明星，并且以类似的金属性和[Fe/H] $> $ -1.0的类似金属种群对银河系的种群不足。在我们的SGR流候选物中，没有发现沿SGR流轨道的金属性的垂直径向梯度。
We constructed a sample of 13,798 stars with $T\rm_{eff}$, log $g$, [Fe/H], radial velocity, proper motions and parallaxes from LAMOST DR5 and Gaia DR2 in the LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) at the Southern Galactic Cap consisting of areas A and B. Using the distributions in both proper motions and radial velocity, we detected very significant overdensities in these two areas. These substructures most likely are portions of Sagittarius (Sgr) stream. With the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, 220 candidates stream members were identified. Based upon distance to the Sun and published models, 106 of these stars are likely to be the members of the Sgr stream. The abundance pattern of these members using [$α$/Fe] from Xiang et al. were found to be similar to Galactic field stars with [Fe/H] $<$ -1.5 and deficient to Milky Way populations at similar metallicities with [Fe/H] $>$ -1.0. No vertical and only small radial gradients in metallicity along the orbit of Sgr stream were found in our Sgr stream candidates.
