Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates
We present identifications and kinematic analysis of 7426 massive (≥8 M _⊙ ) stars in the Small Magellanic Cloud (SMC), using Gaia DR3 data. We used the Gaia ( G _BP − G _RP , G ) color–magnitude diagram to select the population of massive stars, and parallax to omit foreground objects. The spatial...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/adb8de |
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| author | Satoya Nakano Kengo Tachihara Mao Tamashiro |
| author_facet | Satoya Nakano Kengo Tachihara Mao Tamashiro |
| author_sort | Satoya Nakano |
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| description | We present identifications and kinematic analysis of 7426 massive (≥8 M _⊙ ) stars in the Small Magellanic Cloud (SMC), using Gaia DR3 data. We used the Gaia ( G _BP − G _RP , G ) color–magnitude diagram to select the population of massive stars, and parallax to omit foreground objects. The spatial distribution of the 7426 massive star candidates is generally consistent with the spatial distribution of the interstellar medium, such as H α and H i emission. The identified massive stars show inhomogeneous distributions over the galaxy, showing several superstructures formed by massive stars with a several hundred parsec scale. The stellar superstructures defined by the surface density have opposite mean proper motions in the east and west, moving away from each other. Similarly, the mean line-of-sight velocities of the superstructures are larger to the southeast and smaller to the northwest. The different east–west properties of the superstructures’ proper-motion, line-of-sight velocity indicate that the SMC is being stretched by tidal forces and/or ram pressure from the Large Magellanic Cloud to the southeast, thereby rejecting the presence of galactic rotation in the SMC. |
| format | Article |
| id | doaj-art-10dd201cdd9441149aec6b697bcc93d2 |
| institution | OA Journals |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-10dd201cdd9441149aec6b697bcc93d22025-08-20T02:11:34ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127726210.3847/1538-4365/adb8deEvidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star CandidatesSatoya Nakano0https://orcid.org/0009-0001-8036-7296Kengo Tachihara1https://orcid.org/0000-0002-1411-5410Mao Tamashiro2Department of Physics, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan ; nasatoya@a.phys.nagoya-u.ac.jpDepartment of Physics, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan ; nasatoya@a.phys.nagoya-u.ac.jpDepartment of Physics, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan ; nasatoya@a.phys.nagoya-u.ac.jpWe present identifications and kinematic analysis of 7426 massive (≥8 M _⊙ ) stars in the Small Magellanic Cloud (SMC), using Gaia DR3 data. We used the Gaia ( G _BP − G _RP , G ) color–magnitude diagram to select the population of massive stars, and parallax to omit foreground objects. The spatial distribution of the 7426 massive star candidates is generally consistent with the spatial distribution of the interstellar medium, such as H α and H i emission. The identified massive stars show inhomogeneous distributions over the galaxy, showing several superstructures formed by massive stars with a several hundred parsec scale. The stellar superstructures defined by the surface density have opposite mean proper motions in the east and west, moving away from each other. Similarly, the mean line-of-sight velocities of the superstructures are larger to the southeast and smaller to the northwest. The different east–west properties of the superstructures’ proper-motion, line-of-sight velocity indicate that the SMC is being stretched by tidal forces and/or ram pressure from the Large Magellanic Cloud to the southeast, thereby rejecting the presence of galactic rotation in the SMC.https://doi.org/10.3847/1538-4365/adb8deMassive starsSmall Magellanic CloudGalaxy interactionsProper motionsOptical astronomyClustering |
| spellingShingle | Satoya Nakano Kengo Tachihara Mao Tamashiro Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates The Astrophysical Journal Supplement Series Massive stars Small Magellanic Cloud Galaxy interactions Proper motions Optical astronomy Clustering |
| title | Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates |
| title_full | Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates |
| title_fullStr | Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates |
| title_full_unstemmed | Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates |
| title_short | Evidence of Galactic Interaction in the Small Magellanic Cloud Probed by Gaia-selected Massive Star Candidates |
| title_sort | evidence of galactic interaction in the small magellanic cloud probed by gaia selected massive star candidates |
| topic | Massive stars Small Magellanic Cloud Galaxy interactions Proper motions Optical astronomy Clustering |
| url | https://doi.org/10.3847/1538-4365/adb8de |
| work_keys_str_mv | AT satoyanakano evidenceofgalacticinteractioninthesmallmagellaniccloudprobedbygaiaselectedmassivestarcandidates AT kengotachihara evidenceofgalacticinteractioninthesmallmagellaniccloudprobedbygaiaselectedmassivestarcandidates AT maotamashiro evidenceofgalacticinteractioninthesmallmagellaniccloudprobedbygaiaselectedmassivestarcandidates |