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Exploring the origin of the distance bimodality of stars in the periphery of the Small Magellanic Cloud with APOGEE and Gaia.

Authors :
Almeida, Andres
Majewski, Steven R
Nidever, David L
Olsen, Knut A G
Monachesi, Antonela
Kallivayalil, Nitya
Hasselquist, Sten
Choi, Yumi
Povick, Joshua T
Wilson, John C
Geisler, Doug
Lane, Richard R
Nitschelm, Christian
Sobeck, Jennifer S
Stringfellow, Guy S
Source :
Monthly Notices of the Royal Astronomical Society. Apr2024, Vol. 529 Issue 4, p3858-3876. 19p.
Publication Year :
2024

Abstract

The Magellanic Cloud system represents a unique laboratory for study of both interacting dwarf galaxies and the ongoing process of the formation of the Milky Way and its halo. We focus on one aspect of this complex, three-body interaction – the dynamical perturbation of the Small Magellanic Cloud (SMC) by the Large Magellanic Cloud (LMC), and specifically potential tidal effects on the SMC's eastern side. Using Gaia astrometry and the precise radial velocities (RVs) and multielement chemical abundances from Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) Data Release 17, we explore the well-known distance bimodality on the eastern side of the SMC. Through estimated stellar distances, proper motions, and RVs, we characterize the kinematics of the two populations in the bimodality and compare their properties with those of SMC populations elsewhere. Moreover, while all regions explored by APOGEE seem to show a single chemical enrichment history, the metallicity distribution function (MDF), of the 'far' stars on the eastern periphery of the SMC is found to resemble that for the more metal-poor fields of the western periphery, whereas the MDF for the 'near' stars on the eastern periphery resembles that for stars in the SMC Centre. The closer eastern periphery stars also show RVs (corrected for SMC rotation and bulk motion) that are, on average, approaching us relative to all other SMC populations sampled. We interpret these trends as evidence that the near stars on the eastern side of the SMC represent material pulled out of the central SMC as part of its tidal interaction with the LMC. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
529
Issue :
4
Database :
Academic Search Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
176725586
Full Text :
https://doi.org/10.1093/mnras/stae373