Tidally stripped halo stars from the Large Magellanic Cloud in the Galactic North

TL;DR

This study models the tidal stripping of the Large Magellanic Cloud's stellar halo by the Milky Way, predicting streams of stars and identifying candidate stripped stars using Gaia data, revealing the halo extends at least 30° from the LMC.

Contribution

The paper introduces a live N-body model of the MW-LMC interaction and demonstrates a method to identify tidally stripped halo stars using RR Lyrae data from Gaia.

Findings

LMC stellar halo extends at least 30° from the galaxy center.

Several leading arm candidates are identified in the Northern hemisphere.

The model predicts prominent streams of tidally stripped stars.

Abstract

We examine whether the Large Magellanic Cloud (LMC) is currently losing its stellar halo to Milky Way (MW) tides. We present a live $N$-body model for the ongoing MW-LMC interaction that predicts a prominent stream of stars tidally stripped from the progenitor LMC. We use this model to define a strategy to search for stripped material in kinematic space. Of the available stellar tracers, we conclude that samples of RR Lyrae stars provide the highest density of kinematic tracers at present. Using a sample of RR Lyrae stars with Gaia EDR3 astrometry we show that the LMC stellar halo in the Southern Galactic hemisphere extends at least out to $\sim 30^\circ$ from the galaxy centre. In addition, several leading arm candidates are found in the Northern hemisphere as far above the disc plane as $b=+34^\circ$ (at 68$^\circ$ from the LMC).