Relative flux calibration for the Guoshoujing Telescope (LAMOST)  

作　　者：Yi-Han Song A-Li Luo Georges Comte Zhong-Rui Bai Jian-Nan Zhang Wei Du Hao-Tong Zhang Jian-Jun Chen Fang Zuo Yong-Heng Zhao 

机构地区：[1]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China [2]Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China [3]Graduate University of Chinese Academy of Sciences,Beijing 100049,China [4]Observatoire Astronomique Marseille-Provence and Laboratoire d'Astrophysique de Marseille,F-13388 Marseille Cedex,France

出　　处：《Research in Astronomy and Astrophysics》2012年第4期453-464,共12页天文和天体物理学研究（英文版）

基　　金：funded by the National Natural Science Foundation of China (Grant No.10973021)

摘　　要：This paper presents a relative flux calibration method for the Guoshoujing Telescope （LAMOST）, which may be applied to connect a blue spectrum to a red spectrum to build the whole spectrum across the total wavelength range （3700 ～ 9000 A）. In each spectrograph, we estimate the effective temperatures of selected stars using a grid of spectral line indices in the blue spectral range and a comparison with stellar atmosphere models. For each spectrograph, stars of types A and F are selected as pseudo-standard stars, and the theoretical spectra are used to calibrate both the blue （3700 ～ 5900 A） and red spectrograph arms （5700 ～ 9000 A）. Then the spectral response function for these pseudo-standard stars could be used to correct the raw spectra provided by the other fibers of the spectrograph, after a fiber efficiency function has been derived from twilight flat-field exposures. A key problem in this method is the fitting of a pseudo stellar continuum, so we also give a detailed description of this step. The method is tested by comparing a small sample of LAMOST spectra calibrated in this way on stars also observed by the Sloan Digital Sky Survey. The result shows that the T eff estimation and relative flux calibration method are adequate.This paper presents a relative flux calibration method for the Guoshoujing Telescope （LAMOST）, which may be applied to connect a blue spectrum to a red spectrum to build the whole spectrum across the total wavelength range （3700 ～ 9000 A）. In each spectrograph, we estimate the effective temperatures of selected stars using a grid of spectral line indices in the blue spectral range and a comparison with stellar atmosphere models. For each spectrograph, stars of types A and F are selected as pseudo-standard stars, and the theoretical spectra are used to calibrate both the blue （3700 ～ 5900 A） and red spectrograph arms （5700 ～ 9000 A）. Then the spectral response function for these pseudo-standard stars could be used to correct the raw spectra provided by the other fibers of the spectrograph, after a fiber efficiency function has been derived from twilight flat-field exposures. A key problem in this method is the fitting of a pseudo stellar continuum, so we also give a detailed description of this step. The method is tested by comparing a small sample of LAMOST spectra calibrated in this way on stars also observed by the Sloan Digital Sky Survey. The result shows that the T eff estimation and relative flux calibration method are adequate.

关 键 词：techniques： spectroscopic — calibration： methods：data analysis 

分 类 号：TH751[机械工程—仪器科学与技术] TH743[机械工程—精密仪器及机械]