Discovery of NES, an Extended Tidal Structure in the Northeast of the Large Magellanic Cloud

Abstract

We report on the discovery of a new diffuse stellar substructure protruding for >5° from the northeastern rim of the LMC disk. The structure, which we dub the northeast 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 catalog. 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 and the eastern substructures. Particularly noteworthy is that the NES is placed in a region where N -body simulations foresee a bending of the LMC disk 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 northeastern part of the LMC, including NES, shows a complex pattern. Additional data, as well as extensive dynamical modeling, is required to shed light onto the origin of NES as well as on the relationships with the surrounding substructures.