在SDSS DR8恒星光谱中自动搜寻稀有天体
发布时间：2019-03-16 13:30
【摘要】：SDSS DR8海量光谱中包含许多有研究价值的稀有天体,如特殊白矮星(DZ,DQ,DC)、碳星、白矮主序双星、激变变星等,如何在海量光谱中自动搜寻稀有天体有着极其重要的意义。提出一种基于核密度估计和K-近邻(K-nearest neighbor,KNN)相结合的方法在SDSS DR8信噪比大于5的546 383个恒星光谱中搜寻稀有天体。首先对光谱进行高斯核密度估计,选取概率最小的5 000个光谱作为稀有类,概率最大的300 000个光谱作为普通类,然后进行KNN分类,同时也将5 000个稀有光谱的K个最近邻也作为稀有的天体,结果共有21 193条光谱。为了方便分析,对这些光谱聚类后进行人工检查。这些光谱主要包括由于数据缺失、红化、流量定标不准引起的问题光谱、行星状星云、没有物理联系的光谱双星、类星体、特殊白矮星(DZ,DQ,DC)、碳星、白矮主序双星、激变变星等。通过和SIMBAD,NED,ADS及一些主要的文献交叉验证,我们新发现了3个DZ白矮星、1个白矮主序双星、2个伴星为G型星的激变变星,3个激变变星的候选体、6个DC白矮星,1个DC白矮星候选体和1个BLLracertae(BLlac)候选体。还发现了1个有CaⅡ三重发射线和MgⅠ发射线的DA白矮星和1个光谱上表现出发射线的晚M恒星但测光图上像是一个星云或星系。
[Abstract]:The massive spectrum of SDSS DR8 contains many rare objects of research value, such as special white dwarf star (DZ,DQ,DC), carbon star, white dwarf main sequence binary star, cataclysmic star, etc. How to automatically search for rare objects in massive spectra is of great significance. A method based on the combination of kernel density estimation and K-nearest neighbor (K-nearest neighbor,KNN) is proposed to search for rare objects in the spectra of 546,383 stars with SDSS DR8 signal-to-noise ratio greater than 5. In this paper, we first estimate the density of the spectrum by Gao Si's kernel, select the 5,000 spectra with the lowest probability as the rare class, and the 300,000 spectra with the highest probability as the general class, and then carry on the KNN classification. At the same time, K nearest neighbors of 5 000 rare spectra are also regarded as rare objects. The results show that there are 21 193 spectra. In order to facilitate the analysis, after clustering these spectra, the manual examination was carried out. These spectra mainly include problems caused by lack of data, redness, flow calibration, planetary nebulae, spectral binaries that have no physical connection, quasars, special white dwarfs (DZ,DQ,DC), carbon stars, and white dwarf main sequence binary stars. To change the magnitude of a star. Through cross-validation with SIMBAD,NED,ADS and some major literatures, we have discovered three new DZ white dwarf stars, one white dwarf binary star, two mutable stars of type G, three candidates of cataclysmic stars, and six DC white dwarf stars. One DC white dwarf candidate and one BLLracertae (BLlac) candidate. A DA white dwarf star with Ca 鈪，
本文编号：2441464
[Abstract]:The massive spectrum of SDSS DR8 contains many rare objects of research value, such as special white dwarf star (DZ,DQ,DC), carbon star, white dwarf main sequence binary star, cataclysmic star, etc. How to automatically search for rare objects in massive spectra is of great significance. A method based on the combination of kernel density estimation and K-nearest neighbor (K-nearest neighbor,KNN) is proposed to search for rare objects in the spectra of 546,383 stars with SDSS DR8 signal-to-noise ratio greater than 5. In this paper, we first estimate the density of the spectrum by Gao Si's kernel, select the 5,000 spectra with the lowest probability as the rare class, and the 300,000 spectra with the highest probability as the general class, and then carry on the KNN classification. At the same time, K nearest neighbors of 5 000 rare spectra are also regarded as rare objects. The results show that there are 21 193 spectra. In order to facilitate the analysis, after clustering these spectra, the manual examination was carried out. These spectra mainly include problems caused by lack of data, redness, flow calibration, planetary nebulae, spectral binaries that have no physical connection, quasars, special white dwarfs (DZ,DQ,DC), carbon stars, and white dwarf main sequence binary stars. To change the magnitude of a star. Through cross-validation with SIMBAD,NED,ADS and some major literatures, we have discovered three new DZ white dwarf stars, one white dwarf binary star, two mutable stars of type G, three candidates of cataclysmic stars, and six DC white dwarf stars. One DC white dwarf candidate and one BLLracertae (BLlac) candidate. A DA white dwarf star with Ca 鈪，
本文编号：2441464
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