| Color-Redshift Relations and Photometric Redshift Estimations of Quasars in Large Sky Surveys |
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| 引用本文： | Xue-Bing Wu,Wei Zhang and Xu Zhou Department of Astronomy,School of Physics,Peking University,Beijing 100871, National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012. Color-Redshift Relations and Photometric Redshift Estimations of Quasars in Large Sky Surveys[J]. 中国天文和天体物理学报, 2004, 4(1): 17-27 |
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| 作者姓名： | Xue-Bing Wu Wei Zhang and Xu Zhou Department of Astronomy School of Physics Peking University Beijing 100871 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 |
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| 作者单位： | Xue-Bing Wu，Wei Zhang and Xu Zhou Department of Astronomy，School of Physics，Peking University，Beijing 100871; National Astronomical Observatories，Chinese Academy of Sciences，Beijing 100012 |
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| 基金项目： | Supported by the National Natural Science Foundation of China. |
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| 摘 要： | With a recently constructed composite quasar spectrum and the X2 minimization technique, we describe a general method for estimating the photometric redshifts of a large sample of quasars by deriving theoretical color-redshift relations and comparing the theoretical colors with the observed ones. We estimated the photometric redshifts from the 5-band SDSS photometric data of 18678 quasars in the first major data release of SDSS and compared them with their spectroscopic redshifts. The difference is less than 0.1 for 47% of the quasars and less than 0.2 for 68%. Based on the calculation of the theoretical color-color diagrams of stars, galaxies and quasars both on the SDSS system and on the BATC system, we expect that we would be able to select candidates of high redshift quasars more efficaciously with the latter than with the former, provided the BATC survey can detect objects with magnitudes fainter than 21.
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| 关 键 词： | 类星体 频谱 光度测定 红向移动 分光镜 |
Color-Redshift Relations and Photometric Redshift Estimations of Quasars in Large Sky Surveys |
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| Xue-BingWu WeiZhang XuZhou. Color-Redshift Relations and Photometric Redshift Estimations of Quasars in Large Sky Surveys[J]. Chinese Journal of Astronomy and Astrophysics, 2004, 4(1): 17-27 |
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| Authors: | Xue-BingWu WeiZhang XuZhou |
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| Affiliation: | [1]DepartmentofAstronomy,SchoolofPhysics,PekingUniversity,Beijing100871 [2]NationalAstronomicalObservatories,ChineseAcademyofSciences,Beijing100012 |
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| Abstract: | With a recently constructed composite quasar spectrum and the X^2 minimization technique, we describe a general method for estimating the photometric redshifts of a large sample of quasars by deriving theoretical color-redshift relations and comparing the theoretical colors with the observed ones. We estimated the photometric redshifts from the 5-band SDSS photometric data of 18678 quasars in the first major data release of SDSS and compared them with their spectroscopic redshifts. The difference is less than 0.1 for 47% of the quasars and less than 0.2 for 68%. Based on the calculation of the theoretical color-color diagrams of stars, galaxies and quasars both on the SDSS system and on the BATC system, we expect that we would be able to select candidates of high redshift quasars more efficaciously with the latter than with the former, provided the BATC survey can detect objects with magnitudes fainter than 21. |
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| Keywords: | galaxies: photometry - quasars: general - quasars: emission lines - surveys |
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