Two Portions of Sagittarius Stream in the LAMOST Complete Spectroscopic Survey of Pointing Area at Southern Galactic Cap
We constructed a sample of 13,798 stars with Teﬀ , 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 overdensi- ties 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.
The Astrophysical Journal
The American Astronomical Society & IOP Science
Scholarly Commons Citation
Zhao, J. K., Oswalt, T. D., Ye, X. H., Wu, H., Yang, M., Xue, X. X., Chen, Y. Q., Zhan, J. J., & Zhao, G. (2020). Two Portions of Sagittarius Stream in the LAMOST Complete Spectroscopic Survey of Pointing Area at Southern Galactic Cap. The Astrophysical Journal, 904(1). https://doi.org/10.3847/1538-4357/abbc1f