An in-depth Exploration of LAMOST Unknown Spectra Based on Density Clustering

作     者：Hai-Feng Yang Xiao-Na Yin Jiang-Hui Cai Yu-Qing Yang A-Li Luo Zhong-Rui Bai Li-Chan Zhou Xu-Jun Zhao Ya-Ling Xun Hai-Feng Yang;Xiao-Na Yin;Jiang-Hui Cai;Yu-Qing Yang;A-Li Luo;Zhong-Rui Bai;Li-Chan Zhou;Xu-Jun Zhao;Ya-Ling Xun

作者机构：Shanxi Key Laboratory of Big Data Analysis and Parallel ComputingTaiyuan University of Science and TechnologyTaiyuan 030024China School of Computer Science and TechnologyTaiyuan University of Science and TechnologyTaiyuan 030024China School of Computer Science and TechnologyNorth University of ChinaTaiyuan 030051China National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2023年第23卷第5期

页      面：52-65页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. U1931209, 62272336) Projects of Science and Technology Cooperation and Exchange of Shanxi Province (Grant Nos. 202204041101037, 202204041101033) the central government guides local science and technology development funds (Grant No. 20201070) The Fundamental Research Program of Shanxi Province (Grant Nos. 20210302123223, 202103021224275) the Ph D Start-up Foundation of Taiyuan University of Science and Technology (20222119) Guo Shou Jing Telescope (the Large sky Area Multi-Object fiber Spectroscopic Telescope, LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciences. Funding for the project has been provided by the National Development and Reform Commission 

主　　题：methods data analysis-surveys-techniques spectroscopic-site testing-methods analytical 

摘      要：Large sky Area Multi-Object fiber Spectroscopic Telescope(LAMOST) has completed the observation of nearly 20 million celestial objects,including a class of spectra labeled “Unknown. Besides low signal-to-noise ratio,these spectra often show some anomalous features that do not work well with current *** this paper,a total of 637,889 “Unknown spectra from LAMOST DR5 are selected,and an unsupervised-based analytical framework of “Unknown spectra named SA-Frame(Spectra Analysis-Frame) is provided to explore their origins from different *** SA-Frame is composed of three parts:NAPC-Spec clustering,characterization and origin ***,NAPC-Spec(Nonparametric density clustering algorithm for spectra) characterizes different features in the “unknown spectrum by adjusting the influence space and divergence distance to minimize the effects of noise and high dimensionality,resulting in 13 ***,characteristic extraction and representation of clustering results are carried out based on spectral lines and continuum,where these 13 types are characterized as regular spectra with low S/Ns,splicing problems,suspected galactic emission signals,contamination from city light and un-gregarious type ***,a preliminary analysis of their origins is made from the characteristics of the observational targets,contamination from the sky,and the working status of the *** results would be valuable for improving the overall data quality of large-scale spectral surveys.