Physical contact between the +20 km s^-1 cloud and the galactic circumnuclear disk

We report the discovery of physical contact between the Galactic circumnuclear disk (CND) and an adjacent giant molecular cloud. The central 10 pc of our Galaxy has been imaged in molecular lines at millimeter wavelength using the Nobeyama Radio Observatory 45 m radio telescope. In the position-velocity maps of several high-density probe lines, we have found an emission bridge connecting the +20 km s^-1 cloud (M-0.13-0.08) and the negative longitude extension of the CND. The collision between the +20 km s^-1 cloud and the CND may be responsible for the formation of the bridge. This event can promote mass accretion onto the CND and/or into the inner cavity.