A new strategy for estimating photometric redshifts of quasars
YanXia Zhang1; JingYi Zhang1; Xin Jin1; YongHeng Zhao1
Source Publication天文和天体物理学研究:英文版
AbstractBased on the SDSS and SDSS-WISE quasar datasets, we put forward two schemes to estimate the photometric redshifts of quasars. Our schemes are based on the idea that the samples are firstly classified into subsamples by a classifier and then a photometric redshift estimation of different subsamples is performed by a regressor. Random Forest is adopted as the core algorithm of the classifiers, while Random Forest and k NN are applied as the key algorithms of regressors. The samples are divided into two subsamples and four subsamples, depending on the redshift distribution. The performances based on different samples, different algorithms and different schemes are compared. The experimental results indicate that the accuracy of photometric redshift estimation for the two schemes generally improves to some extent compared to the original scheme in terms of the percents in |△z|1+zi< 0.1 and |△z|1+zi<0.2 and mean absolute error. Only given the running speed, k NN shows its superiority to Random Forest. The performance of Random Forest is a little better than or comparable to that of k NN with the two datasets. The accuracy based on the SDSS-WISE sample outperforms that based on the SDSS sample no matter by k NN or by Random Rorest. More information from more bands is considered and helpful to improve the accuracy of photometric redshift estimation. Evidently, it can be found that our strategy to estimate photometric redshift is applicable and may be applied to other datasets or other kinds of objects. Only talking about the percent in |△z|1+zi<0.3, there is still large room for further improvement in the photometric redshift estimation.
Keywordastronomical databases:catalogs (galaxies:)quasars:general methods:statistical techniques:miscellaneous
Funding Project[973 Program] ; [National Natural Science Foundation of China] ; [Alfred P. Sloan Foundation] ; [U.S. Department of Energy Office of Science] ; [Center for High-Performance Computing at the University of Utah] ; [Brazilian Participation Group] ; [Carnegie Institution for Science] ; [Carnegie Mellon University] ; [Chilean Participation Group] ; [French Participation Group] ; [Harvard-Smithsonian Center for Astrophysics] ; [Instituto de Astrofisica de Canarias] ; [The Johns Hopkins University] ; [Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo] ; [Lawrence Berkeley National Laboratory] ; [Leibniz Institut fur Astrophysik Potsdam (AIP)] ; [Max-PlanckInstitut fur Astronomie (MPIA Heidelberg)] ; [Max-PlanckInstitut fur Astrophysik (MPA Garching)] ; [Max-PlanckInstitut fur Extraterrestrische Physik (MPE)] ; [National Astronomical Observatories of China] ; [New Mexico State University] ; [New York University] ; [University of Notre Dame] ; [Observatario Nacional/MCTI] ; [The Ohio State University] ; [Pennsylvania State University] ; [Shanghai Astronomical Observatory] ; [United Kingdom Participation Group] ; [Universidad Nacional Autonoma de Mexico] ; [University of Arizona] ; [University of Colorado Boulder] ; [University of Oxford] ; [University of Portsmouth] ; [University of Utah] ; [University of Virginia] ; [University of Washington] ; [University of Wisconsin] ; [Vanderbilt University] ; [Yale University] ; [National Aeronautics and Space Administration]
Document Type期刊论文
Affiliation1.Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences
Recommended Citation
GB/T 7714
YanXia Zhang,JingYi Zhang,Xin Jin,et al. A new strategy for estimating photometric redshifts of quasars[J]. 天文和天体物理学研究:英文版,2019,19.0(012):223.
APA YanXia Zhang,JingYi Zhang,Xin Jin,&YongHeng Zhao.(2019).A new strategy for estimating photometric redshifts of quasars.天文和天体物理学研究:英文版,19.0(012),223.
MLA YanXia Zhang,et al."A new strategy for estimating photometric redshifts of quasars".天文和天体物理学研究:英文版 19.0.012(2019):223.
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