Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS
We investigate the chemical abundance distributions of the Fornax, Sculptor, Ursa Minor, and Draco dwarf galaxies using Subaru/Hyper Suprime-Cam (HSC) photometric data. The HSC data set, which includes broadband g and i filters and the narrowband NB515 filter, offers sensitivity to iron and magnesiu...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ade679 |
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| author | Jihye Hong Evan N. Kirby Tiffany M. Tang Masashi Chiba Yutaka Komiyama Lauren E. Henderson Itsuki Ogami Timothy C. Beers |
| author_facet | Jihye Hong Evan N. Kirby Tiffany M. Tang Masashi Chiba Yutaka Komiyama Lauren E. Henderson Itsuki Ogami Timothy C. Beers |
| author_sort | Jihye Hong |
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| description | We investigate the chemical abundance distributions of the Fornax, Sculptor, Ursa Minor, and Draco dwarf galaxies using Subaru/Hyper Suprime-Cam (HSC) photometric data. The HSC data set, which includes broadband g and i filters and the narrowband NB515 filter, offers sensitivity to iron and magnesium abundances, as well as surface gravity, enabling the identification of giant stars and foreground dwarfs. For analysis, we selected a total of 6713 giant candidates using a random forest regressor trained on medium-resolution ( R ∼ 6000) Keck/Deep Imaging Multi-Object Spectrograph spectroscopic data. Our analysis reveals the extent of radial metallicity gradients in the galaxies. Such trends, not detectable in earlier studies, are now captured owing to the substantially enlarged sample size and areal coverage provided by the HSC data. These results are also consistent with chemical abundance patterns previously observed in the central regions through spectroscopic studies. Furthermore, we infer that Fornax underwent extended star formation, whereas Sculptor formed both metal-poor and metal-rich stars over a shorter time. Ursa Minor and Draco appear to have experienced brief, intense star formation episodes leading to nearly extinguished star formation. This study underscores the critical role of the expanded HSC data set in revealing chemical gradients that were previously inaccessible. Future work incorporating additional spectra of metal-poor stars and age-sensitive isochrone modeling will enable more accurate maps of chemical abundance distributions. |
| format | Article |
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| institution | DOAJ |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-1574417f87e5424d847bf9cee050fbbf2025-08-20T03:18:53ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198914810.3847/1538-4357/ade679Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOSJihye Hong0https://orcid.org/0000-0002-2453-0853Evan N. Kirby1https://orcid.org/0000-0001-6196-5162Tiffany M. Tang2https://orcid.org/0000-0002-8079-6867Masashi Chiba3https://orcid.org/0000-0002-9053-860XYutaka Komiyama4https://orcid.org/0000-0002-3852-6329Lauren E. Henderson5https://orcid.org/0000-0001-6207-4388Itsuki Ogami6https://orcid.org/0000-0001-8239-4549Timothy C. Beers7https://orcid.org/0000-0003-4573-6233Department of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USA; Joint Institute for Nuclear Astrophysics—Center for the Evolution of the Elements (JINA-CEE) , USADepartment of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USADepartment of Applied and Computational Mathematics and Statistics, University of Notre Dame , Notre Dame, IN 46556, USAAstronomical Institute, Tohoku University , 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, JapanDepartment of Advanced Sciences, Faculty of Science and Engineering, Hosei University , 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584, JapanDepartment of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USANational Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; The Institute of Statistical Mathematics , 10-3 Midoricho, Tachikawa, Tokyo, 190-8562, JapanDepartment of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USA; Joint Institute for Nuclear Astrophysics—Center for the Evolution of the Elements (JINA-CEE) , USAWe investigate the chemical abundance distributions of the Fornax, Sculptor, Ursa Minor, and Draco dwarf galaxies using Subaru/Hyper Suprime-Cam (HSC) photometric data. The HSC data set, which includes broadband g and i filters and the narrowband NB515 filter, offers sensitivity to iron and magnesium abundances, as well as surface gravity, enabling the identification of giant stars and foreground dwarfs. For analysis, we selected a total of 6713 giant candidates using a random forest regressor trained on medium-resolution ( R ∼ 6000) Keck/Deep Imaging Multi-Object Spectrograph spectroscopic data. Our analysis reveals the extent of radial metallicity gradients in the galaxies. Such trends, not detectable in earlier studies, are now captured owing to the substantially enlarged sample size and areal coverage provided by the HSC data. These results are also consistent with chemical abundance patterns previously observed in the central regions through spectroscopic studies. Furthermore, we infer that Fornax underwent extended star formation, whereas Sculptor formed both metal-poor and metal-rich stars over a shorter time. Ursa Minor and Draco appear to have experienced brief, intense star formation episodes leading to nearly extinguished star formation. This study underscores the critical role of the expanded HSC data set in revealing chemical gradients that were previously inaccessible. Future work incorporating additional spectra of metal-poor stars and age-sensitive isochrone modeling will enable more accurate maps of chemical abundance distributions.https://doi.org/10.3847/1538-4357/ade679Dwarf spheroidal galaxiesLocal GroupNarrow band photometryRandom ForestsStellar abundances |
| spellingShingle | Jihye Hong Evan N. Kirby Tiffany M. Tang Masashi Chiba Yutaka Komiyama Lauren E. Henderson Itsuki Ogami Timothy C. Beers Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS The Astrophysical Journal Dwarf spheroidal galaxies Local Group Narrow band photometry Random Forests Stellar abundances |
| title | Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS |
| title_full | Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS |
| title_fullStr | Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS |
| title_full_unstemmed | Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS |
| title_short | Estimating Fe and Mg Abundances in the Milky Way Dwarf Galaxies Using Subaru/HSC and DEIMOS |
| title_sort | estimating fe and mg abundances in the milky way dwarf galaxies using subaru hsc and deimos |
| topic | Dwarf spheroidal galaxies Local Group Narrow band photometry Random Forests Stellar abundances |
| url | https://doi.org/10.3847/1538-4357/ade679 |
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