A Catalog of Quasar Candidates Identified by Astrometric and Mid-infrared Methods in Gaia EDR3  

作　　者：Qiqi Wu Shilong Liao Zhaoxiang Qi Hao Luo Zhenghong Tang Zihuang Cao 

机构地区：[1]Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]National Astronomical Observatories,Chinese Academy of Sciences,Beijing.100101,China

出　　处：《Research in Astronomy and Astrophysics》2023年第2期82-98,共17页天文和天体物理学研究（英文版）

基　　金：supported by the Youth Innovation Promotion Association CAS with Certificate Number 2022259;the grants from the Natural Science Foundation of Shanghai through grant 21ZR1474100;the National Natural Science Foundation of China(NSFC)through grants 12173069,and 11703065;the science research grants from the China Manned Space Project with NO.CMS-CSST-2021-A12 and NO.CMS-CSST-2021-B10。

摘　　要：Quasars are very important in materializing the reference frame.The excess emission of active galactic nuclei(AGNs) in the mid-infrared band can be used to identify quasar candidates.As extremely distant and point-like objects,quasars also could be further selected by an astrometry method.Increasing the number of reliable quasar candidates is necessary in characterizing the properties of Gaia astrometric solution and evaluating the reliability of Gaia’s own quasars classification.We identify quasars by using appropriate All WISE [W1-W2] color and different combinations of astrometric criteria.Together with the contamination and completeness,the magnitude,astrometric properties,density distribution,and the morphological indexes of these selected quasars are evaluated.We obtain a quasar candidate catalog of 1,503,373 sources,which contains 1,186,690 candidates(78.9%) in common with the Gaia EDR3_AGN catalog and 316,683 newly identified quasar candidates.The completeness of this catalog is around 80% compared to LQAC5,and the purity of the overall catalog is about 90%.We also found that the purity of quasar candidates selected by this method will decrease in the crowded sky area and the region with less WISE observations.

关 键 词：(galaxies:)quasars general-parallaxes-catalogs-astrometry 

分 类 号：P158[天文地球—天文学]