Abstract:
The internal kinematics of the Large Magellanic Cloud (LMC) disk have been modeled by several studies using
different tracers with varying coverage, resulting in a range of parameters. Here, we model the LMC disk using
1705 star clusters and field stars, based on a robust Markov Chain Monte Carlo method, using Gaia DR3 data. The
dependency of the model parameters on the age, coverage, and strength of the clusters are also presented. This is
the first comprehensive 2D kinematic study using star clusters. Red clump (RC) stars and young main-sequence
stars are also modeled for comparison. The clusters and field stars are found to have distinctly different kinematic
centers, disk inclination, position angle of the line of nodes, and scale radius. We also note a significant radial
variation of the disk parameters. Clusters and young stars are found to have a large residual proper motion and a
relatively large velocity dispersion when compared to the RC field population, which could be due to perturbation
from the bar and spiral arms. We trace the presence of the large residual proper motion and noncircular motion
among clusters likely to be due to the bar and detect a decrease in the scale radius as a result of the possible
evolution of the bar. The kinematically deviant clusters point to a spatiotemporal disturbance in the LMC disk,
matching with the expected impact factor and time of the recent collision between the LMC and the Small
Magellanic Cloud.
