Peculiar rotations of molecular gas in M82 - Keplerian disk and slowly rotating halo

High-resolution, high-sensitivity observations of the CO(J=2-1) lines in the galaxy M82 have revealed that the rotation of the gas disk is Keplerian, which suggests that the galaxy has no massive halo. The extended molecular gas halo, extending up to ±2 kpc above the galactic plane, shows very slow rotation and indicates that the halo gas has been ejected from the central region in angular momentum conservation