Chemical Abundances in the Nuclear Star Cluster of the Milky Way: alpha-Element Trends and Their Similarities with the Inner Bulge
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arXiv
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| Autori principali: | , , , , , , , , , , , , , , , , , |
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| Natura: | Preprint |
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2024
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| author | Ryde, N. Nandakumar, G. Schultheis, M. Kordopatis, G. di Matteo, P. Haywood, M. Schödel, R. Nogueras-Lara, F. Rich, R. M. Thorsbro, B. Mace, G. Agertz, O. Amarsi, A. M. Kocher, J. Molero, M. Origlia, L. Pagnini, G. Spitoni, E. |
| author_facet | Ryde, N. Nandakumar, G. Schultheis, M. Kordopatis, G. di Matteo, P. Haywood, M. Schödel, R. Nogueras-Lara, F. Rich, R. M. Thorsbro, B. Mace, G. Agertz, O. Amarsi, A. M. Kocher, J. Molero, M. Origlia, L. Pagnini, G. Spitoni, E. |
| contents | A chemical characterization of the Galactic Center is essential for understanding its formation and structural evolution. Trends of alpha-elements, such as Mg, Si, and Ca, serve as powerful diagnostic tools, offering insights into star-formation rates and gas-infall history. However, high extinction has previously hindered such studies. In this study, we present a detailed chemical abundance analysis of M giants in the Milky Way's Nuclear Star Cluster (NSC), focusing on alpha-element trends with metallicity. High-resolution, near-infrared spectra were obtained using the IGRINS spectrograph on the Gemini South telescope for nine M giants. Careful selection of spectral lines, based on a solar-neighborhood control sample of 50 M giants, was implemented to minimize systematic uncertainties. Our findings show enhanced alpha-element abundances in the predominantly metal-rich NSC stars, consistent with trends in the inner bulge. The NSC stars follow the high-[alpha/Fe] envelope seen in the solar vicinity's metal-rich population, indicating a high star-formation rate. The alpha-element trends decrease with increasing metallicity, also at the highest metallicities. Our results suggest the NSC population likely shares a similar evolutionary history with the inner bulge, challenging the idea of a recent dominant star formation burst. This connection between the NSC and the inner-disk sequence suggests that the chemical properties of extragalactic NSCs of Milky Way type galaxies could serve as a proxy for understanding the host galaxies' evolutionary processes. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_04528 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Chemical Abundances in the Nuclear Star Cluster of the Milky Way: alpha-Element Trends and Their Similarities with the Inner Bulge Ryde, N. Nandakumar, G. Schultheis, M. Kordopatis, G. di Matteo, P. Haywood, M. Schödel, R. Nogueras-Lara, F. Rich, R. M. Thorsbro, B. Mace, G. Agertz, O. Amarsi, A. M. Kocher, J. Molero, M. Origlia, L. Pagnini, G. Spitoni, E. Astrophysics of Galaxies Solar and Stellar Astrophysics A chemical characterization of the Galactic Center is essential for understanding its formation and structural evolution. Trends of alpha-elements, such as Mg, Si, and Ca, serve as powerful diagnostic tools, offering insights into star-formation rates and gas-infall history. However, high extinction has previously hindered such studies. In this study, we present a detailed chemical abundance analysis of M giants in the Milky Way's Nuclear Star Cluster (NSC), focusing on alpha-element trends with metallicity. High-resolution, near-infrared spectra were obtained using the IGRINS spectrograph on the Gemini South telescope for nine M giants. Careful selection of spectral lines, based on a solar-neighborhood control sample of 50 M giants, was implemented to minimize systematic uncertainties. Our findings show enhanced alpha-element abundances in the predominantly metal-rich NSC stars, consistent with trends in the inner bulge. The NSC stars follow the high-[alpha/Fe] envelope seen in the solar vicinity's metal-rich population, indicating a high star-formation rate. The alpha-element trends decrease with increasing metallicity, also at the highest metallicities. Our results suggest the NSC population likely shares a similar evolutionary history with the inner bulge, challenging the idea of a recent dominant star formation burst. This connection between the NSC and the inner-disk sequence suggests that the chemical properties of extragalactic NSCs of Milky Way type galaxies could serve as a proxy for understanding the host galaxies' evolutionary processes. |
| title | Chemical Abundances in the Nuclear Star Cluster of the Milky Way: alpha-Element Trends and Their Similarities with the Inner Bulge |
| topic | Astrophysics of Galaxies Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2412.04528 |