Redshift Determination for Quasar Based on Similarity Measure

Abstract. With the advent of very large redshift surveys, automatic redshift measurement is becoming increasingly important. This paper presents a similarity measure based cross-correlation method for the red-shift determination of quasar spectra. Cross-correlation is measured only for the redshift candidates that are determined by the emission line fea-tures of the observed spectrum. The similarity measure is defined as the weighted sum of several similarity evidences. Compared with the traditional cross-correlation based methods, our method can be used for higher redshift determination. Compared with the methods based on spectral line matching, our method is less sensitive to the quality of spec-tral line extraction. Experiment results indicate the high performance of the method.