Discovery of NES, an extended tidal structure in the North-East of the Large Magellanic Cloud

TL;DR

This paper reports the discovery of a new diffuse stellar structure called NES in the North-East of the Large Magellanic Cloud, identified through Gaia data and Gaussian Mixture Modeling, suggesting complex tidal interactions.

Contribution

It introduces the NES as a previously unknown tidal sub-structure in the LMC, filling a gap between known features and providing new observational evidence of tidal effects.

Findings

NES extends 5 degrees from LMC rim

Coherent radial motions observed in the tidal structures

NES aligns with regions predicted by tidal interaction models

Abstract

We report on the discovery of a new diffuse stellar sub-structure protruding for 5 degrees from the North-Eastern rim of the LMC disc. The structure, that we dub North-East Structure (NES), was identified by applying a Gaussian Mixture Model to a sample of strictly selected candidate members of the Magellanic System, extracted from the Gaia EDR3 catalogue. The NES fills the gap between the outer LMC disk and other known structures in the same region of the LMC, namely the Northern tidal arm (NTA) and the Eastern sub-structures (ES). Particularly noteworthy is that the NES is placed in a region where N-body simulations foresee a bending of the LMC disc due to tidal stresses induced by the MW. The velocity field in the plane of the sky indicates that the complex of tidal structures in the North-Eastern part of the LMC, including NES, is subject to coherent radial motions. Additional data, as well as extensive dynamical modeling, is required to shed light on the origin of NES as well as on the relationships with the surrounding substructures.