Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud
We model the kinematics of the Small Magellanic Cloud (SMC) by analyzing the proper motions (PMs) from Gaia DR3 of nine different stellar populations, including young main-sequence (MS) stars (<2 Gyr), red giant branch stars, red clump stars, red giants with line-of-sight velocities, and three gr...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ada55f |
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| author | S. R. Dhanush A. Subramaniam S. Subramanian |
| author_facet | S. R. Dhanush A. Subramaniam S. Subramanian |
| author_sort | S. R. Dhanush |
| collection | DOAJ |
| description | We model the kinematics of the Small Magellanic Cloud (SMC) by analyzing the proper motions (PMs) from Gaia DR3 of nine different stellar populations, including young main-sequence (MS) stars (<2 Gyr), red giant branch stars, red clump stars, red giants with line-of-sight velocities, and three groups of star clusters. This analysis is carried out using a robust Markov Chain Monte Carlo method, to derive up to seven kinematic parameters. We trace the evolution from a nonrotating flattened elliptical system, as mapped by the old population, to a rotating highly stretched disk structure, as denoted by the young MS stars and clusters (<400 Myr). We estimate that the inclination i (∼58°–82°) decreases and the position angle Θ (∼180°–240°) increases with age. We estimate an asymptotic velocity of ∼49–89 km s ^−1 with a scale radius of ∼6–9 kpc for the young MS populations, with velocity dispersion of ∼11 km s ^−1 , suggesting a rotation-supported disk structure. Our models estimate a line-of-sight extension of ∼30 kpc, in agreement with observations. We identify four regions of the SMC showing anomalies in the residual PM: the East Anomaly, the Southeast Anomaly (SEA), the South Anomaly, and the West Anomaly. The SEA appears like an infalling feature and is identified for the first time. The tidal imprints observed in the residual PM of the SMC suggest that its evolution is considerably shaped by the recent interaction with the Large Magellanic Cloud. |
| format | Article |
| id | doaj-art-1397291be87a40dc879f4299a0ab957a |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-1397291be87a40dc879f4299a0ab957a2025-02-05T09:09:51ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198017310.3847/1538-4357/ada55fUnraveling the Kinematic and Morphological Evolution of the Small Magellanic CloudS. R. Dhanush0https://orcid.org/0009-0007-0388-3143A. Subramaniam1https://orcid.org/0000-0003-4612-620XS. Subramanian2https://orcid.org/0000-0002-5331-6098Indian Institute of Astrophysics , Bangalore, 560034, India ; srdhanushsr@gmail.com; Pondicherry University , R.V. Nagar, Kalapet, Puducherry, 605014, IndiaIndian Institute of Astrophysics , Bangalore, 560034, India ; srdhanushsr@gmail.comIndian Institute of Astrophysics , Bangalore, 560034, India ; srdhanushsr@gmail.comWe model the kinematics of the Small Magellanic Cloud (SMC) by analyzing the proper motions (PMs) from Gaia DR3 of nine different stellar populations, including young main-sequence (MS) stars (<2 Gyr), red giant branch stars, red clump stars, red giants with line-of-sight velocities, and three groups of star clusters. This analysis is carried out using a robust Markov Chain Monte Carlo method, to derive up to seven kinematic parameters. We trace the evolution from a nonrotating flattened elliptical system, as mapped by the old population, to a rotating highly stretched disk structure, as denoted by the young MS stars and clusters (<400 Myr). We estimate that the inclination i (∼58°–82°) decreases and the position angle Θ (∼180°–240°) increases with age. We estimate an asymptotic velocity of ∼49–89 km s ^−1 with a scale radius of ∼6–9 kpc for the young MS populations, with velocity dispersion of ∼11 km s ^−1 , suggesting a rotation-supported disk structure. Our models estimate a line-of-sight extension of ∼30 kpc, in agreement with observations. We identify four regions of the SMC showing anomalies in the residual PM: the East Anomaly, the Southeast Anomaly (SEA), the South Anomaly, and the West Anomaly. The SEA appears like an infalling feature and is identified for the first time. The tidal imprints observed in the residual PM of the SMC suggest that its evolution is considerably shaped by the recent interaction with the Large Magellanic Cloud.https://doi.org/10.3847/1538-4357/ada55fSmall Magellanic CloudDwarf galaxiesStar clustersTidal interaction |
| spellingShingle | S. R. Dhanush A. Subramaniam S. Subramanian Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud The Astrophysical Journal Small Magellanic Cloud Dwarf galaxies Star clusters Tidal interaction |
| title | Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud |
| title_full | Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud |
| title_fullStr | Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud |
| title_full_unstemmed | Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud |
| title_short | Unraveling the Kinematic and Morphological Evolution of the Small Magellanic Cloud |
| title_sort | unraveling the kinematic and morphological evolution of the small magellanic cloud |
| topic | Small Magellanic Cloud Dwarf galaxies Star clusters Tidal interaction |
| url | https://doi.org/10.3847/1538-4357/ada55f |
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