CO (J=2−1) observations of the molecular cloud complex in the Galactic center

We report a large scale mapping observation of the Galactic center region in the CO (J=2−1) line using the Tokyo‐NRO 60 cm survey telescope. Distribution of the CO (J=2−1) emission in the I‐V plane suggests that molecular clouds forms a huge complex (Nuclear Molecular cloud Complex, NMC). Tracers of star formation activities in the last 106–108 years show that star formation has occurred in a ring ∼100 pc in radius. Relative to this Star Forming Ring, the molecular gas is distributed mainly on the positive longitude side. This may indicate that much of the gas in NMC is in transient orbit to fall into the star forming ring or to the nucleus in the near future.