A New Redshift Measuring Method for Low-Quality Galaxy Spectra Based on Multi Resolution Fusion Distance
PAN Jing-chang1, LUO A-li1, 2, WEI Peng2, JIANG Bin1, LI Yin-bi2, ZHENG Qiang3
1. School of Mechanical, Electrical & Information Engineering, Shandong University, Weihai, Weihai 264209, China 2. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 3. College of Computer and Control Engineering，Yantai University，Yantai 264005, China
Abstract：The redshift measurement of galaxy spectrum is a key issue in large astronomical spectral survey. Its goal is to extract the redshift from spectrum, which is caused the Doppler Effect. With the development of the extragalactic sky survey project, the distance (redshift) of the observed targets is becoming further. As a result, the magnitude of the observed objects becomes darker and the spectral quality becomes poorer. Therefore, how to effectively and accurately measure the redshift from these low quality spectra is becoming an important problem in the extragalactic survey. Considering the spectral features and the data character, a new definition of multi-resolution fusion distance for low quality spectra is proposed. In this paper, we put forward a redshift measuring method for low quality galaxy spectra. This method combines the spectral features with different resolutions. The template spectrum and the spectrum to measure are reduced to the resolution and then a distance is computed by combining the offset of the above two spectra in different wavelengths.Then, a fusion distance is weighted averaged from the distances with different resolutions. In this paper, the effect of signal-to-noise ratio (SNR) on the measuring accuracy of the proposed method is discussed. The measuring accuracy is larger than 90% when the SNR is larger than 5. A large number of experiments show that the method proposedin this paper is very efficient in measuring the redshift of the low-quality galaxy spectra and the measuring error has nothing to do with the redshift value. The proposed method can be applied in redshift measurement of galaxies for the large-scale survey data.
潘景昌1，罗阿理1, 2，韦 鹏2，姜 斌1，李荫碧2，郑 强3. 基于多分辨率融合距离的低质量星系光谱红移测量方法[J]. 光谱学与光谱分析, 2016, 36(05): 1521-1525.
PAN Jing-chang1, LUO A-li1, 2, WEI Peng2, JIANG Bin1, LI Yin-bi2, ZHENG Qiang3. A New Redshift Measuring Method for Low-Quality Galaxy Spectra Based on Multi Resolution Fusion Distance. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(05): 1521-1525.
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