Chemo-Dynamical Tagging in the Outskirts: The Origins of Stellar Substructures in the Magellanic Clouds

Abstract

We present the first detailed chemical analysis from APOGEE-2S observations of stars in six regions of recently discovered substructures in the outskirts of the Magellanic Clouds extending to 20 degrees from the LMC center. We also present, for the first time, the metallicity and alpha-abundance radial gradients of the LMC and SMC out to 11 degrees and 6 degrees, respectively. Our chemical tagging includes 13 species including light, alpha, and Fe-peak elements. We find that the abundances of all of these chemical elements in stars populating two regions in the northern periphery - along the northern "stream"-like feature - show good agreement with the chemical patterns of the LMC, and thus likely have an LMC origin. For substructures located in the southern periphery of the LMC, we find more complex chemical and kinematical signatures, indicative of a mix of LMC-like and SMC-like populations. However, the southern region closest to the LMC shows better agreement with the LMC, whereas that closest to the SMC shows a much better agreement with the SMC chemical pattern. When combining this information with 3-D kinematical information for these stars, we conclude that the southern region closest to the LMC has likely an LMC origin, whereas that closest to the SMC has an SMC origin, and the other two southern regions have a mix of LMC and SMC origins. Our results add to the evidence that the southern substructures of the LMC periphery are the product of close interactions between the LMC and SMC, and thus likely hold important clues that can constrain models of their detailed dynamical histories.

21 pages, 15 figures, 9 tables; Accepted for publication in A&A

References in corpus (26)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Dartmouth Stellar Evolution Database
• A distance to the Large Magellanic Cloud that is precise to one per cent
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
• Target Selection for the SDSS-IV APOGEE-2 Survey
• The Origin of the Magellanic Stream and Its Leading Arm
• APOGEE Chemical Abundance Patterns of the Massive Milky Way Satellites
• Disentangling the Galactic Halo with APOGEE: I. Chemical and Kinematical Investigation of Distinct Metal-Poor Populations
• New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE survey
• The Chemical Enrichment History of the Large Magellanic Cloud
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• The Magellanic Bridge: The Nearest Purely Tidal Stellar Population
• Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall
• An Ultra-Faint Galaxy Candidate Discovered in Early Data from the Magellanic Satellites Survey
• Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey
• Final Targeting Strategy for the SDSS-IV APOGEE-2N Survey
• The recent LMC-SMC collision: Timing and impact parameter constraints from comparison of Gaia LMC disk kinematics and N-body simulations
• The VMC survey -- XLIV: Mapping metallicity trends in the Large Magellanic Cloud using near-infrared passbands
• The Magellanic Edges Survey I. Description and First Results
• Deciphering the Kinematic Structure of the Small Magellanic Cloud through its Red Giant Population
• Ca II Triplet Spectroscopy of Small Magellanic Cloud Red Giants. V. Abundances and Velocities for 12 Massive Clusters
• Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud

Cited by in corpus (3)

• The role of accreted and in situ populations in shaping the stellar halos of low-mass galaxies
• CAPOS: The bulge Cluster APOgee Survey VIII. Final ASPCAP results for all clusters
• Mapping the Distorted Dark Matter Distribution of the LMC-SMC System Prior to Milky Way Infall with Basis Function Expansions