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A comprehensive view of the morphology of the Magellanic Clouds in the near-infrared

Published onJun 01, 2020
A comprehensive view of the morphology of the Magellanic Clouds in the near-infrared

I present the morphology of the Magellanic Clouds (MCs) using data from the VISTA survey of the Magellanic Clouds system (VMC) and Vista Hemisphere Survey (VHS), respectively, targeting the MCs and their stellar periphery. I used near-infrared colour-magnitude diagrams to define different stellar populations for which I estimated the median ages using theoretical evolutionary models. The morphology maps reveal detailed features in the central regions that are characterised for the first time at spatial resolutions of 0.13 kpc (LMC) and 0.16 kpc (SMC). In the LMC, I find that main sequence stars show coherent structures that grow more enhanced with age and trace the multiple spiral arms of the galaxy while intermediate-age and old stars, despite tracing a regular and symmetrical morphology, show central clumps and hints of spiral arms. In the outskirts, tidal features related to the LMC and SMC dynamical history are detected extending up to 20 deg north from the centre of the LMC while diffuse stellar substructures are revealed for the first time in the eastern side of its disc. In the SMC, intermediate-age populations show signatures of elongation towards the Magellanic Bridge that can be attributed to the LMC-SMC interaction 200 Myr ago. They also show irregular central features potentially suggesting that the inner SMC has also been influenced by tidal interactions. In this contribution, I also present the luminosity function of red clump stars in the periphery of the SMC (>4 deg). A bimodality in magnitude has been discovered along with those stars in the main body of the galaxy whose most likely explanation is a population of foreground stars that has been stripped from the SMC. I show that this double red clump feature can be traced in the eastern part of the SMC up to 6 deg away from its centre. This work reflects the complex dynamical history of the Magellanic Clouds and the observed stellar distributions will help enable a new generation of numerical models to understand the LMC-SMC and MCs-Milky Way interaction histories.


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