Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures
We present a structural analysis of 138 compact elliptical galaxies (cEs) in the redshift range of z < 0.05 using the Sloan Digital Sky Survey (SDSS) DR12 data. We perform single- and double-component Sérsic model fitting to their SDSS r -band surface brightness profiles. By dividing cEs into tho...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ade4c3 |
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| author | Jinwon Yi Soo-Chang Rey Suk Kim Youngdae Lee |
| author_facet | Jinwon Yi Soo-Chang Rey Suk Kim Youngdae Lee |
| author_sort | Jinwon Yi |
| collection | DOAJ |
| description | We present a structural analysis of 138 compact elliptical galaxies (cEs) in the redshift range of z < 0.05 using the Sloan Digital Sky Survey (SDSS) DR12 data. We perform single- and double-component Sérsic model fitting to their SDSS r -band surface brightness profiles. By dividing cEs into those with [cE(w)] and without [cE(w/o)] a bright host galaxy, we find a significant structural dichotomy: the majority (∼85%) of cE(w)s exhibit single-component profiles, while a similar proportion (∼85%) of isolated cE(w/o)s display double-component profiles, characterized by a compact, inner component and a diffuse, disk-like outer component. These results suggest that host-associated cE(w)s primarily form through the tidal stripping of larger progenitors, resulting in a compact bulge-like core. In contrast, isolated cE(w/o)s appear to form intrinsically at early epochs, likely through gas-rich mergers, and retain disk-like outer structures. The Sérsic index distribution of cE(w)s with single-component structure indicates progenitor types ranging from pseudobulge to classical bulge, supported by differences in stellar populations. A small fraction of cEs, including double-component cE(w)s and single-component cE(w/o)s, suggests complex evolutionary channels involving environmental capture or ejection. Our results emphasize that the structural characteristics of cEs, specifically the presence or absence of an extended outer envelope, serve as a crucial diagnostic tool to distinguish tidally stripped remnants from intrinsically formed low-mass cEs in isolation. |
| format | Article |
| id | doaj-art-943353d51a7449d98202c13d248f9d6d |
| institution | Matheson Library |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj-art-943353d51a7449d98202c13d248f9d6d2025-08-01T05:24:37ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198913210.3847/1538-4357/ade4c3Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal StructuresJinwon Yi0Soo-Chang Rey1https://orcid.org/0000-0002-0041-6490Suk Kim2https://orcid.org/0000-0003-3474-9047Youngdae Lee3https://orcid.org/0000-0002-6261-1531Department of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of Korea ; screy@cnu.ac.krDepartment of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of Korea ; screy@cnu.ac.krDepartment of Astronomy and Space Science & Research Institute of Natural Sciences, Chungnam National University , Daejeon 34134, Republic of KoreaDepartment of Astronomy and Space Science & Research Institute of Natural Sciences, Chungnam National University , Daejeon 34134, Republic of KoreaWe present a structural analysis of 138 compact elliptical galaxies (cEs) in the redshift range of z < 0.05 using the Sloan Digital Sky Survey (SDSS) DR12 data. We perform single- and double-component Sérsic model fitting to their SDSS r -band surface brightness profiles. By dividing cEs into those with [cE(w)] and without [cE(w/o)] a bright host galaxy, we find a significant structural dichotomy: the majority (∼85%) of cE(w)s exhibit single-component profiles, while a similar proportion (∼85%) of isolated cE(w/o)s display double-component profiles, characterized by a compact, inner component and a diffuse, disk-like outer component. These results suggest that host-associated cE(w)s primarily form through the tidal stripping of larger progenitors, resulting in a compact bulge-like core. In contrast, isolated cE(w/o)s appear to form intrinsically at early epochs, likely through gas-rich mergers, and retain disk-like outer structures. The Sérsic index distribution of cE(w)s with single-component structure indicates progenitor types ranging from pseudobulge to classical bulge, supported by differences in stellar populations. A small fraction of cEs, including double-component cE(w)s and single-component cE(w/o)s, suggests complex evolutionary channels involving environmental capture or ejection. Our results emphasize that the structural characteristics of cEs, specifically the presence or absence of an extended outer envelope, serve as a crucial diagnostic tool to distinguish tidally stripped remnants from intrinsically formed low-mass cEs in isolation.https://doi.org/10.3847/1538-4357/ade4c3Compact objectsCompact galaxiesCompact dwarf galaxiesElliptical galaxiesGalaxy evolutionGalaxy formation |
| spellingShingle | Jinwon Yi Soo-Chang Rey Suk Kim Youngdae Lee Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures The Astrophysical Journal Compact objects Compact galaxies Compact dwarf galaxies Elliptical galaxies Galaxy evolution Galaxy formation |
| title | Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures |
| title_full | Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures |
| title_fullStr | Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures |
| title_full_unstemmed | Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures |
| title_short | Formation Pathways of Compact Elliptical Galaxies: Perspective of Internal Structures |
| title_sort | formation pathways of compact elliptical galaxies perspective of internal structures |
| topic | Compact objects Compact galaxies Compact dwarf galaxies Elliptical galaxies Galaxy evolution Galaxy formation |
| url | https://doi.org/10.3847/1538-4357/ade4c3 |
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