Automatic Normalization and Equivalent-Width Measurement of High-Resolution Stellar Spectra
Jingkun Zhao, Gang Zhao, Yuqin Chen, Jianrong Shi, Yujuan Liu, Juyong Zhang · 天文和天体物理学研究：英文版 · 2006
It is well known that normalization, radial velocity correction and equivalent-width measurement of high-resolution stellar spectra are time-consuming work. In order to improve the efficiency we present an automatic method for these routines. The continuum is determined by fitting the `high points' in the spectrum. After continuum normalization, the program automatically searches for the position of the Hα line and obtains a rough radial velocity, then computes an accurate radial velocity by cross-correlation between the given spectrum and the solar spectrum. In this method, the equivalent-width is automatically measured using Gaussian fitting. A comparison between our results and those from traditional analysis shows that the typical error for equivalent width is around 3.8% in our method. Developing such automatic routines does not mean to replace the interactive reduction method: it is just for a quick extraction of information from the spectra, especially those obtained in large sky surveys.