光谱预处理及其对星系/类星体分类结果的影响

由于噪声、畸变和观测环境等因素的影响,在天体光谱自动处理之前,需要对它进行相应的预处理.研究巡天光谱的预处理(数据格式和流量标准化)对光谱自动分析的影响.分析了同数据格式对光谱及其谱线特征的影响和格式标准化研究的必要性;通过分析光谱流量数量级的不确定性及其特点,提出了流量数量级变化的基本模型,并给出了相应的标准化方法.通过星系和类星体的分类实验,结果表明:1)采用对数波长数据格式对光谱的自动分类更有利;2)验证了所提出的流量标准化模型的合理性,以及所给流量标准化方法良好的性能.特别需要指出的是,文献中通常采用的流量标准化方法在光谱自动分类中的效果反而是较差的.

Spectral Preprocess and Its Influence on Galaxy and Quasar Classification

Celestial spectra should be preprocessed before automated classification to eliminate the disturbance of noise,unstableness of observation environment,and flux aber- rance,etc.In this work,methods for data representation and flux normalization are studied. First,the necessity of proper data representation and flux normalization is clarified by an- alyzing their influence on spectra automated analysis.Second,a flux varying model is pro- posed and several different normalization schemes are assessed.While on galaxy and quasar classification,experiment results show that the log-wavelength representation performs bet- ter than the wavelength representation,and surprisingly the commonly used normalization scheme performs worse than others,for example,a median-based one.