{"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/sdss-iv-mastar-quantification-and-abatement","title":"SDSS-IV MaStar: Quantification and Abatement of Interstellar Absorption in the Largest Empirical Stellar Spectral Library","arxiv_id":"2502.09707","date":"2025-02-13","proceeding":null,"authors":["Kate H. R. Rubin","Kyle B. Westfall","Claudia Maraston","Daniel Thomas","Renbin Yan","J. Christopher Howk","Erick Aguirre","Kaelee S. Parker","David R. Law"],"abstract":"We assess the impact of CaII 3934,3969 and NaI 5891,5897 absorption arising in the interstellar medium (ISM) on the SDSS-IV MaNGA Stellar Library (MaStar) and produce corrected spectroscopy for 80% of the 24,162-star catalog. We model the absorption strength of these transitions as a function of stellar distance, Galactic latitude, and dust reddening based upon high-spectral resolution studies. With this model, we identify 6342 MaStar stars that have negligible ISM absorption ($W^\\mathrm{ISM}$(CaII K) $<0.07$ Ang and $W^\\mathrm{ISM}$(NaI 5891) $<0.05$ Ang). For 12,110 of the remaining stars, we replace their NaI D profile (and their CaII profile for effective temperatures $T_{\\rm eff}>9000$ K) with a coadded spectrum of low-ISM stars with similar $T_{\\rm eff}$, surface gravity, and metallicity. For 738 additional stars with $T_{\\rm eff}>9000$ K, we replace these spectral regions with a matching ATLAS9-based BOSZ model. This results in a mean reduction in $W$(CaII K) ($W$(NaI D)) of $0.4-0.7$ Ang ($0.6-1.1$ Ang) for hot stars ($T_{\\rm eff}>7610$ K), and a mean reduction in $W$(NaI D) of $0.1-0.2$ Ang for cooler stars. We show that interstellar absorption in simple stellar population (SSP) model spectra constructed from the original library artificially enhances $W$(CaII K) by $\\gtrsim20\\%$ at young ages ($<400$ Myr); dramatically enhances the strength of stellar NaI D in starbursting systems (by ${\\gtrsim}50\\%$); and enhances stellar NaI D in older stellar populations (${\\gtrsim}10$ Gyr) by ${\\gtrsim}10\\%$. We provide SSP spectra constructed from the cleaned library, and discuss the implications of these effects for stellar population synthesis analyses constraining stellar age, [Na/Fe] abundance, and the initial mass function.","url_abs":"https://arxiv.org/abs/2502.09707v1","url_pdf":"https://arxiv.org/pdf/2502.09707v1.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":"sdss-iv-mastar-quantification-and-abatement","repo_url":"https://github.com/sdss/mangadap","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}