Stellar substructures in the periphery of the Magellanic Clouds with the VISTA Hemisphere Survey from the red clump and other tracers

TL;DR

This study uses near-infrared data from the VISTA Hemisphere Survey to analyze the stellar outskirts of the Magellanic Clouds, revealing new substructures and confirming complex stellar distributions related to their interaction history.

Contribution

It identifies new stellar substructures around the Magellanic Clouds and confirms a bi-modal distance distribution of red clump stars, advancing understanding of their interaction history.

Findings

Discovery of new substructures on the eastern side of the LMC and northern SMC.

Confirmation of bi-modal distance distribution of red clump stars in the SMC.

Detection of background and foreground structures possibly linked to tidal features.

Abstract

We study the morphology of the stellar periphery of the Magellanic Clouds in search of substructure using near-infrared imaging data from the VISTA Hemisphere Survey (VHS). Based on the selection of different stellar populations using the ($J-K_\mathrm{s}$, $K_\mathrm{s}$) colour-magnitude diagram, we confirm the presence of substructures related to the interaction history of the Clouds and find new substructures on the easter side of the LMC disc which may be owing to the influence of the Milky Way, and on the northern side of the SMC, which is probably associated to the ellipsoidal structure of the galaxy. We also study the luminosity function of red clump stars in the SMC and confirm the presence of a bi-modal distance distribution, in the form of a foreground population. We find that this bi-modality is still detectable in the eastern regions of the galaxy out to a 10 deg distance from its centre. Additionally, a background structure is detected in the North between 7 and 10 deg from the centre which might belong to the Counter Bridge, and a foreground structure is detected in the South between 6 and 8 deg from the centre which might be linked to the Old Bridge.