Steps Towards a Fully Automated Classification and Redshiftmeasurement Pipeline for LAMOST Spectra. I. Continuum level and wavelength estimation for galaxies

作     者：A-Li Luo and Yong-Heng Zhao National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 

作者机构：National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 

出 版 物：《Chinese Journal of Astronomy and Astrophysics》 (中国天文和天体物理学报（英文版）)

年 卷 期：2001年第1卷第6期

页      面：563-572页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

主　　题：methods: data analysis   techniques: spectroscopic   galaxies: emission lines   galaxies: absorption lines 

摘      要：The Large Sky-Area Multi-Object Spectroscopic Telescope (LAMOST) under construction by the National Astronomical Observatories will yield up to four thousand multi-fiber spectra of stars and galaxies per field. The present series of papers describes the automated data-reduction pipeline currently being designed in order to cope with the anticipated flood of spectrographic data. In this preliminary paper, we present an automated method for estimating the continuum level, the positions of strong lines and the 4000 A break in galaxy spectra. In order to obtain detailed information on the continuum, we use a wavelet filter bank. After continuum fitting, our software searches for a 4000 A break and distinguishes between emission-line galaxies (ELGs) and non-ELGs according to whether the break is small or large. It then searches for strong lines and measures the intensities of emission lines and the equivalent widths of absorption lines. For non-ELGs, the absorption lines are identified automatically yielding redshift measurements.