Volume 618, October 2018
|Number of page(s)||7|
|Section||Catalogs and data|
|Published online||24 October 2018|
Identifying quasars with astrometric and mid-infrared methods from APOP and ALLWISE⋆
Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Rd, 200030 Shanghai, PR China
2 School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing, 100049, PR China
3 INAF, Astrophysical Observatory of Torino. Via Osservatorio 20, Pino Torinese (Torino) 10025, Italy
4 National Astronomical Observatory, Chinese Academy of Sciences, PR China
Accepted: 10 June 2018
Context. Quasars are spatially stationary, and they are essential objects in astrometry when defining reference frames. However, the census of quasars is far from complete. Mid-infared colors can be used to find quasar candidates because active galactic nuclei (AGNs) show a peculiar appearance in mid-infrared color, but these methods are incapable of separating quasars from AGNs.
Aims. The aim of our study is to use astrometric and mid-infrared methods to select quasars and get a reliable quasar candidates catalog.
Methods. We used a near-zero proper motion criterion in conjuction with WISE [W1–W2] color to select quasar candidates. The [W1–W2] color criterion is defined by the linear boundary of two samples: LAMOST DR5 quasars, which serve as the quasar sample, and LAMOST DR5 stars and galaxies, which serve as the non-quasar sample. The contamination and completeness are evaluated.
Results. We present a catalog of 662 753 quasar candidates, with a completeness of about 75% and a reliability of 77.2%.
Key words: catalogs / quasars: general / proper motions / galaxies: active / infrared: galaxies
The catalog of AGN candidates is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (184.108.40.206) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/618/A144
© ESO 2018
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