Статья

Self-consistent Stellar Radial Velocities from LAMOST Medium-resolution Survey DR7

Bo ZhangDepartment of Astronomy, Beijing Normal University, Beijing 100875, People’s Republic of China; [email protected]Jiao LiKey Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People’s Republic of ChinaFan YangDepartment of Astronomy, Beijing Normal University, Beijing 100875, People’s Republic of China; [email protected]Jian-Ping XiongKey Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People’s Republic of ChinaJian-Ning FuDepartment of Astronomy, Beijing Normal University, Beijing 100875, People’s Republic of China; [email protected]Chao LiuKey Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People’s Republic of ChinaHao TianKey Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People’s Republic of ChinaYin-Bi LiKey Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People’s Republic of ChinaJiaxin WangDepartment of Astronomy, Beijing Normal University, Beijing 100875, People’s Republic of China; [email protected]Cai-Xia LiangNational Cancer Center, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100021, People’s Republic of ChinaYutao ZhouDepartment of Astronomy, School of Physics, Peking University, Beijing 100871, People’s Republic of ChinaWeikai ZongDepartment of Astronomy, Beijing Normal University, Beijing 100875, People’s Republic of China; [email protected]Chengqun YangShanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, People’s Republic of ChinaNian LiuPhysics and Space Science College, China West Normal University, Nanchong 637002, People’s Republic of ChinaYonghui HouNanjing Institute of Astronomical Optics & Technology, National Astronomical Observatories, Chinese Academy of Sciences, Nanjing 210042, People’s Republic of China

2021en

ABI

Аннотация

Abstract Radial velocity (RV) is among the most fundamental physical quantities obtainable from stellar spectra and is rather important in the analysis of time-domain phenomena. LAMOST Medium-resolution Survey (MRS) DR7 contains five million single-exposure stellar spectra with spectral resolution R ∼ 7500. However, the temporal variation of the RV zero-points (RVZPs) of the MRS, which makes the RVs from multiple epochs inconsistent, has not been addressed. In this paper, we measure the RVs of 3.8 million single-exposure spectra (for 0.6 million stars) with signal-to-noise ratios (S/N) higher than 5 based on the cross-correlation function method, and propose a robust method to self-consistently determine the RVZPs exposure by exposure for each spectrograph with the help of Gaia DR2 RVs. Such RVZPs are estimated for 3.6 million RVs and can reach a mean precision of ∼0.38 km s −1 . The result of the temporal variation of RVZPs indicates that our algorithm is efficient and necessary before we use the absolute RVs to perform time-domain analyses. Validating the results with APOGEE DR16 shows that our absolute RVs can reach an overall precision of 0.84/0.80 km s −1 in the blue/red arm at 50 < S/N < 100 and of 1.26/1.99 km s −1 at 5 < S/N < 10. The cumulative distribution function of the standard deviations of multiple RVs ( N obs ≥ 8) for 678 standard stars reaches 0.45/0.54, 1.07/1.39, and 1.45/1.86 km s −1 in the blue/red arm at the 50%, 90%, and 95% levels, respectively. Catalogs of the RVs, RVZPs, and selected candidate RV standard stars are available at https://github.com/hypergravity/paperdata .

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Идентификаторы

DOI: 10.3847/1538-4365/ac0834

Цитирования и источники

Цитирований: 2Использованных источников: 0

Показатели — AkademScholar