Gaia DR3 stars LMC/MW membership

Using this classifier we select three samples of candidate LMC stars with different degrees of completeness and purity; we validate these classification results using different test samples and we compare them with the results from the selection strategy used in the Gaia Collaboration papers, based only on proper motions. We analyse the resulting velocity profiles and maps for the different LMC samples, and we check how these results change when using also the line-of-sight velocities, available for a subset of stars.

We show that the contamination in the samples from Milky Way stars affects basically the results for the outskirts of the LMC, and that the analysis formalism used in absence of line-of-sight velocities does not bias the results for the kinematics in the inner disc. For the first time, we perform a kinematic analysis of the LMC using samples with the full three dimensional velocity information from Gaia DR3. The detailed 2D and 3D kinematic analysis of the LMC internal dynamics show that: the dynamics in the inner disc is mainly bar dominated; the kinematics on the spiral arm over-density seem to be dominated by an inward motion and a rotation faster than that of the disc in the piece of the arm attached to the bar; contamination of MW stars seem to dominate the outer parts of the disc and mainly affects old evolutionary phases; uncertainties in the assumed disc morphological parameters and line-of-sight velocity of the LMC can in some cases have significant effects in the analysis.