Line profile analysis of an astronomical spectrograph with a laser frequency comb  

作　　者：Fei Zhao Gang Zhao Gaspare Lo Curto Hui-Juan Wang Yu-Juan Liu Liang Wang Wei Wang 

机构地区：[1]Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment,School of Space Science and Physics,Shandong University [4]European Southern Observatory,Karl-Schwarzschild-Str. 2,85748 Garching,Germany

出　　处：《Research in Astronomy and Astrophysics》2014年第8期1037-1045,共9页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 11233004 and 11390371);supported by the Specialized Research Fund for Shandong Provincial Key Laboratory

摘　　要：We present a study of the spectral line shape associated with a High Resolution Spectrograph on the 2.16 m telescope at the Xinglong Observing Station of National Astronomical Observatories, Chinese Academy of Sciences. This measurement is based on modeling the instrumental line shape obtained by unresolved modes from a Yb-fiber mode-locked laser frequency comb. With the current repetition rate of 250 MHz and 26 GHz mode spacing on the spectrograph, we find the absolute variation of the line center, 0.0597 pixel in the direction of the CCDs, and 0.00275 pixel （～3 m s^-1） for relative variation in successive exposures on a short timescale. A novel double-Gaussian model is presented to improve the quality of the fit by a factor of 2.47 in a typical single exposure. We also use analysis with raw moments and central moments to characterize the change in line shape across the detector. A trend in charge transfer efficiency can be found on the E2V 4096 ×4096 CCD that provides a correction for wavelength calibration aiming to reach a level of precision for radial velocity below 1 m s^- 1.We present a study of the spectral line shape associated with a High Resolution Spectrograph on the 2.16 m telescope at the Xinglong Observing Station of National Astronomical Observatories, Chinese Academy of Sciences. This measurement is based on modeling the instrumental line shape obtained by unresolved modes from a Yb-fiber mode-locked laser frequency comb. With the current repetition rate of 250 MHz and 26 GHz mode spacing on the spectrograph, we find the absolute variation of the line center, 0.0597 pixel in the direction of the CCDs, and 0.00275 pixel （～3 m s^-1） for relative variation in successive exposures on a short timescale. A novel double-Gaussian model is presented to improve the quality of the fit by a factor of 2.47 in a typical single exposure. We also use analysis with raw moments and central moments to characterize the change in line shape across the detector. A trend in charge transfer efficiency can be found on the E2V 4096 ×4096 CCD that provides a correction for wavelength calibration aiming to reach a level of precision for radial velocity below 1 m s^- 1.

关 键 词：TECHNIQUES radial velocities -- instrumentation laser frequency comb 

分 类 号：P111.4[天文地球—天文学]