2007ApJ...656L..61O

We present a combined analysis of the kinematics of the Large Magellanic Cloud through its H I gas, carbon stars, and red supergiant stars. After correcting the line-of-sight velocities for the recent accurate measurement of the LMC's space motion, we find that each kinematic tracer clearly defines a flat rotation curve with similar shape but different amplitude for each tracer: 61 km/s for the carbon stars, 80 km/s for the H I, and 107 km/s for the red supergiants. Previously identified tidal H I features are seen to harbor numerous carbon stars, with the tidally disturbed stars comprising 7%-15% of the total sample. This discovery implies that we cannot depend on the carbon star sample alone to construct a reliable model of the LMC's gravitational potential. We also find red supergiants with peculiar kinematics, but their association with tidal features is unclear and may instead be interacting with supergiant H I shell SGS4. In addition, although the local velocity dispersion of the red supergiants is small, ∼8 km/s, their velocity dispersion about the carbon star rotation solution is 17 km/s, equal to the velocity dispersion of the carbon stars themselves. We thus appear to be witnessing the tidal heating of the LMC's stellar disk.