English | 简体中文

You are here

LAMOST Spectrograph Response Curves: Stability and Application to flux calibration

Proceeded by one-year Pilot Survey, the LAMOST Regular Surveys started in September 2012, and have produced more than 600 million of high quality spectra until now. Recently, the research group ( Bing Du, A-Li Luo, Xiao Kong et al. 2016 ) from National Astronomical Observatories studied the stability of the LAMOST spectrograph Response Curves. The result shows that the average response curve of each spectrograph ( henceforth ASPSRC ) is relatively stable with statisticalStability larger than 90%. From the comparison between each ASPSRC and the SRCs for the same spectrograph obtained by the LAMOST 2D pipeline, the researchers find that the ASPSRCs are good enough to use for the flux calibration. The ASPSRCs increased the number of LAMOST spectra for release, which confirmed the reliability of this method to a certain extent. Comparing those same targets with the Sloan Digital Sky Survey (SDSS), the relative flux differences between SDSS spectra and LAMOST spectra with the ASPSRC method are less than 10% ( see fig 1 ), which underlines that the ASPSRC method is feasible for LAMSOT flux calibration. This work has been published in ApJS,2016.



 Fig 1  Distribution of the ratios of spectral pairs observed by both LAMOST and SDSS, each point is a ratio value of one pair, the contour represent the distribution of the ratio values of 1746 spectral pairs. The smoothed mean and standard deviation of the ratios, as a function of wavelength, are shown by the solid and dashed curves.