Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters
Extinction toward the Galactic Center (GC) is extreme and limits observations of its stars to the infrared. In addition, the extinction varies on scales of arcseconds. It is therefore highly challenging to distinguish between different stars photometrically and to identify young, massive, or interme...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acd5cc |
| _version_ | 1797694191426338816 |
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| author | Shogo Nishiyama Naoya Funamoto Rainer Schödel |
| author_facet | Shogo Nishiyama Naoya Funamoto Rainer Schödel |
| author_sort | Shogo Nishiyama |
| collection | DOAJ |
| description | Extinction toward the Galactic Center (GC) is extreme and limits observations of its stars to the infrared. In addition, the extinction varies on scales of arcseconds. It is therefore highly challenging to distinguish between different stars photometrically and to identify young, massive, or intermediate-age stars that can trace recent star formation. Here we report the results of near-infrared imaging observations of a $6\buildrel{\,\prime}\over{.} 0\times 3\buildrel{\,\prime}\over{.} 3$ region at the GC that encompasses the northwest part of the nuclear star cluster and parts of the nuclear stellar disk. We carried out the observations with the wide-field camera MOIRCS of the Subaru Telescope, using three narrowband (NB) filters. Two of the filters trace the stellar continuum, while we use the third one to measure the strength of the CO absorption features that are prominent in the spectra of cool giants, shallower in the spectra of warmer stars, and absent in young massive stars. Thus, we aim to distinguish between old late-type giants and young and intermediate-age stars. We have found 131 candidates of young and intermediate-age stars. The magnitude limit is ≈11.25 in the extinction-corrected K -band magnitude. The contamination of the candidates by old giants is estimated to be 26%. We show that our method allows us to identify correctly four out of five spectroscopically confirmed massive stars, and 68 of 75 spectroscopically confirmed cool stars (91%). Our results suggest that imaging observations with a CO NB filter can be complementary to other methods to identify massive stars in the GC. |
| first_indexed | 2024-03-12T02:53:24Z |
| format | Article |
| id | doaj.art-a4b6f61c6ecb4cc693c9bb170baeda2d |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T02:53:24Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-a4b6f61c6ecb4cc693c9bb170baeda2d2023-09-03T15:26:41ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01951214810.3847/1538-4357/acd5ccSearch for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband FiltersShogo Nishiyama0https://orcid.org/0000-0002-9440-7172Naoya Funamoto1Rainer Schödel2https://orcid.org/0000-0001-5404-797XMiyagi University of Education , 149 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan ; shogo-n@staff.miyakyo-u.ac.jpMiyagi University of Education , 149 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan ; shogo-n@staff.miyakyo-u.ac.jpInstituto de Astrofísica de Andalucía (IAA)-CSIC , Glorieta de la Astronomía s/n, E-18008 Granada, SpainExtinction toward the Galactic Center (GC) is extreme and limits observations of its stars to the infrared. In addition, the extinction varies on scales of arcseconds. It is therefore highly challenging to distinguish between different stars photometrically and to identify young, massive, or intermediate-age stars that can trace recent star formation. Here we report the results of near-infrared imaging observations of a $6\buildrel{\,\prime}\over{.} 0\times 3\buildrel{\,\prime}\over{.} 3$ region at the GC that encompasses the northwest part of the nuclear star cluster and parts of the nuclear stellar disk. We carried out the observations with the wide-field camera MOIRCS of the Subaru Telescope, using three narrowband (NB) filters. Two of the filters trace the stellar continuum, while we use the third one to measure the strength of the CO absorption features that are prominent in the spectra of cool giants, shallower in the spectra of warmer stars, and absent in young massive stars. Thus, we aim to distinguish between old late-type giants and young and intermediate-age stars. We have found 131 candidates of young and intermediate-age stars. The magnitude limit is ≈11.25 in the extinction-corrected K -band magnitude. The contamination of the candidates by old giants is estimated to be 26%. We show that our method allows us to identify correctly four out of five spectroscopically confirmed massive stars, and 68 of 75 spectroscopically confirmed cool stars (91%). Our results suggest that imaging observations with a CO NB filter can be complementary to other methods to identify massive stars in the GC.https://doi.org/10.3847/1538-4357/acd5ccGalactic centerInfrared photometryNarrow band photometry |
| spellingShingle | Shogo Nishiyama Naoya Funamoto Rainer Schödel Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters The Astrophysical Journal Galactic center Infrared photometry Narrow band photometry |
| title | Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters |
| title_full | Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters |
| title_fullStr | Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters |
| title_full_unstemmed | Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters |
| title_short | Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters |
| title_sort | search for young and intermediate age stellar populations in the galactic center with subaru moircs and co narrowband filters |
| topic | Galactic center Infrared photometry Narrow band photometry |
| url | https://doi.org/10.3847/1538-4357/acd5cc |
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