Evidence of a counterrotating core in the Large Magellanic Cloud

Abstract

Stellar radial velocity in the central region of the Large Magellanic Cloud (LMC) is used to estimate the radial velocity curve along various position angles (PA) including the line of nodes (LON). The central part of the radial velocity profile, along the LON, shows a V-shaped profile - a clear indication of counterrotation. The counterrotating region and the secondary bar have similar location and PA. The origin of the counter-rotating core could be internal(secondary bar) or external(accretion). To explain the observed velocity profile, we propose the existence of two disks in the inner LMC, with one counterrotating. This two disk model is found to match the HI velocities as well. Two disks with different LON and velocity profiles can create regions which are kinematically and spatially separated. Predicted such locations are found to match the observed locations where the HI clouds are found to have two velocities.