{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/self-consistent-stellar-radial-velocities","title":"Self-consistent Stellar Radial Velocities from LAMOST Medium-Resolution Survey (MRS) DR7","arxiv_id":"2105.11624","date":"2021-05-25","proceeding":null,"authors":["Bo Zhang","Jiao Li","Fan Yang","Jian-Ping Xiong","Jian-Ning Fu","Chao Liu","Hao Tian","Yin-Bi Li","Jia-Xin Wang","Cai-Xia Liang","Yu-Tao Zhou","Wei-kai Zong","Cheng-Qun Yang","Nian Liu","Yong-Hui Hou"],"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. The LAMOST Medium-Resolution Survey (MRS) DR7 contains 5 million single-exposure stellar spectra at spectral resolution $R\\sim7\\,500$. However, the temporal variation of the RV zero-points (RVZPs) of the MRS survey, which makes the RVs from multiple epochs inconsistent, has not been addressed. In this paper, we measure the RVs of the 3.8 million single-exposure spectra (for 0.6 million stars) with signal-to-noise ratio (SNR) higher than 5 based on cross-correlation function (CCF) method, and propose a robust method to self-consistently determine the RVZPs exposure-by-exposure for each spectrograph with the help of \\textit{Gaia} DR2 RVs. Such RVZPs are estimated for 3.6 million RVs and can reach a mean precision of $\\sim 0.38\\,\\mathrm{km\\,s}^{-1}$. 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 analysis. Validating the results with APOGEE DR16 shows that our absolute RVs can reach an overall precision of 0.84/0.80 $\\mathrm{km\\,s}^{-1}$ in the blue/red arm at $50<\\mathrm{SNR}<100$, while 1.26/1.99 $\\mathrm{km\\,s}^{-1}$ at $5<\\mathrm{SNR}<10$. The cumulative distribution function (CDF) of the standard deviations of multiple RVs ($N_\\mathrm{obs}\\geq 8$) for 678 standard stars reach 0.45/0.54, 1.07/1.39, and 1.45/1.86 $\\mathrm{km\\,s}^{-1}$ in the blue/red arm at 50\\%, 90\\%, and 95\\% levels, respectively. The catalogs of the RVs, RVZPs, and selected candidate RV standard stars are available at \\url{https://github.com/hypergravity/paperdata}.","url_abs":"https://arxiv.org/abs/2105.11624v1","url_pdf":"https://arxiv.org/pdf/2105.11624v1.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"self-consistent-stellar-radial-velocities","repo_url":"https://github.com/hypergravity/paperdata","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"tf","reach":null},{"paper_slug":"self-consistent-stellar-radial-velocities","repo_url":"https://github.com/hypergravity/berliner","is_official":1,"mentioned_in_paper":0,"mentioned_in_github":0,"framework":"none","reach":null},{"paper_slug":"self-consistent-stellar-radial-velocities","repo_url":"https://github.com/hypergravity/laspec","is_official":1,"mentioned_in_paper":0,"mentioned_in_github":0,"framework":"none","reach":null},{"paper_slug":"self-consistent-stellar-radial-velocities","repo_url":"https://github.com/hypergravity/regli","is_official":1,"mentioned_in_paper":0,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}