Internal dynamics of the Large Magellanic Cloud from Gaia DR2

TL;DR

This study utilizes Gaia DR2 proper motion data of half a million red giants to map the Large Magellanic Cloud's internal kinematics, revealing its rotation curve, velocity dispersions, and orientation.

Contribution

It provides a detailed 2D kinematic map of the LMC and measures its dynamical properties using Gaia DR2 data, offering new insights into its internal dynamics.

Findings

Circular velocity reaches 90 km/s at 5 Kpc

Velocity dispersion ranges from 30-40 km/s in the center to 15-20 km/s at 7 Kpc

The galaxy's orientation and rotation profile are characterized

Abstract

We use the proper motions (PM) of half a million red giant stars in Large Magellanic Cloud measured by Gaia to construct a 2d kinematic map of mean PM and its dispersion across the galaxy, out to 7 Kpc from its centre. We then explore a range of dynamical models and measure the rotation curve, mean azimuthal velocity, velocity dispersion profiles, and the orientation of the galaxy. We find that the circular velocity reaches 90 km/s at 5 Kpc, and that the velocity dispersion ranges from 30-40 km/s in the galaxy centre to 15-20 km/s at 7 Kpc.