The first data release of LAMOST low-resolution single-epoch spectra

作     者：白仲瑞 张昊彤 袁海龙 樊东卫 何勃亮 雷亚娟 董义乔 余思成 赵永恒 张勇 侯永辉 禇耀泉 Zhong-Rui Bai;Hao-Tong Zhang;Hai-Long Yuan;Dong-Wei Fan;Bo-Liang He;Ya-Juan Lei;Yi-Qiao Dong;Si-Cheng Yu;Yong-Heng Zhao;Yong Zhang;Yong-Hui Hou;Yao-Quan Chu

作者机构：CAS Key Laboratory of Optical AstronomyNational Astronomical ObservatoriesBeijing 100101China National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China National Astronomical Data CenterBeijing 100101China Nanjing Institute of Astronomical Optics&TechnologyNational Astronomical ObservatoriesChinese Academy of SciencesNanjing 210042China University of Science and Technology of ChinaHefei 230026China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2021年第21卷第10期

页      面：73-85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] 

基　　金：support of the National Key R&D Program of China(2019YFA0405000) the National Natural Science Foundation of China(NSFC)(Grant Nos.12090040 and 12090041) the support of NSFC(Grant No.11973054) the support of the Youth Innovation Promotion Association of Chinese Academy of Sciences(id.2020060) supported by Cultivation Project for LAMOST Scientific Payoff Research Achievement of CAMS-CAS Funding for the project has been provided by the National Development and Reform Commission。 

主　　题：surveys stars:general methods:data analysis 

摘      要：LAMOST Data Release 5,covering 17000 deg^(2) from-10°to 80°in declination,contains 9 million co-added low-resolution spectra of celestial objects,each spectrum combined from repeat exposure of two to tens of times during Oct 2011 to Jun 2017.In this paper,we present the spectra of individual exposures for all the objects in LAMOST Data Release 5.For each spectrum,the equivalent width of 60lines from 11 different elements are calculated with a new method combining the actual line core and fitted line wings.For stars earlier than F type,the Balmer lines are fitted with both emission and absorption profiles once two components are detected.Radial velocity of each individual exposure is measured by minimizing χ^(2) between the spectrum and its best template.The database for equivalent widths of spectral lines and radial velocities of individual spectra are available online.Radial velocity uncertainties with different stellar type and signal-to-noise ratio are quantified by comparing different exposure of the same objects.We notice that the radial velocity uncertainty depends on the time lag between observations.For stars observed in the same day and with signal-to-noise ratio higher than 20,the radial velocity uncertainty is below 5 km s^(-1),and increases to 10 km s^(-1) for stars observed in different nights.