Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters
Stellar population synthesis (SPS) models are a key tool for deriving the age, metallicity, radial velocity, and reddening of star clusters from their integrated spectra. Using a sample of 129 star clusters with high-quality spectra, we analyze the uncertainties associated with selecting an empirica...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/addaad |
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| author | Randa Asa’d Paula R. T. Coelho Johina M. John Igor V. Chilingarian Gustavo Bruzual Stephane Charlot |
| author_facet | Randa Asa’d Paula R. T. Coelho Johina M. John Igor V. Chilingarian Gustavo Bruzual Stephane Charlot |
| author_sort | Randa Asa’d |
| collection | DOAJ |
| description | Stellar population synthesis (SPS) models are a key tool for deriving the age, metallicity, radial velocity, and reddening of star clusters from their integrated spectra. Using a sample of 129 star clusters with high-quality spectra, we analyze the uncertainties associated with selecting an empirical versus a theoretical stellar spectral library in the SPS models. We find that the fits from the different models agree on the goodness-of-fit metrics and inferred reddening. However, the derived age and metallicity can be affected by the choice of the stellar library, with synthetic libraries tending to give lower age and metallicity, especially for spectra with low signal-to-noise ratio. Ages and reddening values from SSP-equivalent fits are consistent with the multipopulation fits; however, SSP-equivalent metallicities are affected by the coarse coverage of the SPS grid in [Fe/H]. When comparing the spectral fitting results with the literature, we find that (1) all models underestimate age for old and metal-poor systems, and (2) on average, SPS models based on synthetic stellar libraries better match the isochrone ages and metallicities from high-resolution stellar spectroscopy. |
| format | Article |
| id | doaj-art-5fa2d8425b9f453694cb58a4335a4ab6 |
| institution | DOAJ |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-5fa2d8425b9f453694cb58a4335a4ab62025-08-20T02:39:25ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0117028510.3847/1538-3881/addaadSemiempirical versus Theoretical Stellar Population Models: A Comparison with Star ClustersRanda Asa’d0https://orcid.org/0000-0003-4861-6624Paula R. T. Coelho1https://orcid.org/0000-0003-1846-4826Johina M. John2Igor V. Chilingarian3https://orcid.org/0000-0002-7924-3253Gustavo Bruzual4Stephane Charlot5American University of Sharjah , Physics Department, P.O. Box 26666, Sharjah, UAE ; raasad@aus.eduUniversidade de São Paulo , Instituto de Astronomia, Geofísica e Ciencias Atmosféricas, Rua do Matão 1226, 05508-090 São Paulo, BrazilAmerican University of Sharjah , Physics Department, P.O. Box 26666, Sharjah, UAE ; raasad@aus.eduCenter for Astrophysics—Harvard and Smithsonian , 60 Garden St. MS09, Cambridge, MA, 02138, USA; Sternberg Astronomical Institute, M.V. Lomonosov Moscow State University , 13 Universitetsky prospect, Moscow, 119991, RussiaInstituto de Radioastronomía y Astrofísica , UNAM, Campus Morelia, Michoacán, C.P. 58089, MéxicoSorbonne Université , CNRS, UMR7095, Institut d’Astrophysique de Paris, F-75014 Paris, FranceStellar population synthesis (SPS) models are a key tool for deriving the age, metallicity, radial velocity, and reddening of star clusters from their integrated spectra. Using a sample of 129 star clusters with high-quality spectra, we analyze the uncertainties associated with selecting an empirical versus a theoretical stellar spectral library in the SPS models. We find that the fits from the different models agree on the goodness-of-fit metrics and inferred reddening. However, the derived age and metallicity can be affected by the choice of the stellar library, with synthetic libraries tending to give lower age and metallicity, especially for spectra with low signal-to-noise ratio. Ages and reddening values from SSP-equivalent fits are consistent with the multipopulation fits; however, SSP-equivalent metallicities are affected by the coarse coverage of the SPS grid in [Fe/H]. When comparing the spectral fitting results with the literature, we find that (1) all models underestimate age for old and metal-poor systems, and (2) on average, SPS models based on synthetic stellar libraries better match the isochrone ages and metallicities from high-resolution stellar spectroscopy.https://doi.org/10.3847/1538-3881/addaadStar clusters |
| spellingShingle | Randa Asa’d Paula R. T. Coelho Johina M. John Igor V. Chilingarian Gustavo Bruzual Stephane Charlot Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters The Astronomical Journal Star clusters |
| title | Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters |
| title_full | Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters |
| title_fullStr | Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters |
| title_full_unstemmed | Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters |
| title_short | Semiempirical versus Theoretical Stellar Population Models: A Comparison with Star Clusters |
| title_sort | semiempirical versus theoretical stellar population models a comparison with star clusters |
| topic | Star clusters |
| url | https://doi.org/10.3847/1538-3881/addaad |
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