主成份分析和交叉相关的红移测量

Galaxy Redshift Determination by Use of Principal Component Analysis and Cross Correlation

提出了一种新的红移测量方法.首先进行谱线提取,并利用谱线信息确定红移候选;然后,根据红移候选对目标光谱和模板光谱进行交叉相关计算,最大相关值对应的红移候选为目标光谱的红移.采用的静止模板是利用主成份分析构造的.与已有的基于交叉相关的方法相比,本文方法可测量的红移范围大,受谱线提取效果的影响较小.实验结果表明:该方法优于基于谱线匹配的方法,正确率达到95%以上.

With the advent of very large redshift surveys, automatic redshift determination is becoming increasingly important. This paper presents a novel method of redshift determination. Firstly, spectral lines are extracted and used to determine the redshift candidates; then, the cross-correlation between the observed spectrum and the templates is measured for the candidates, and the redshift candidate corresponding to the largest correlation is chosen as the redshift of the observed spectrum. The templates were constructed by principal component analysis. Compared with the traditional cross-correlation based methods, this method can be used for high redshift spectra. Compared with the methods based on spectral line matching, this method is less sensitive to the quality of spectral line extraction. Experiments show that this method is superior to the methods based on spectral line matching, and the correct rate reaches 95 % above.