We present high-frequency Karl G. Jansky Very Large Array ( VLA ) continuum and spectral line ( NH _ { 3 } , H64 \alpha , and H63 \alpha ) observations of the Galactic Center Radio Arc region , covering the Sickle H II region , the Quintuplet cluster , and molecular clouds M0.20 - 0.033 and M0.10 - 0.08 .
These observations show that the two velocity components of M0.20 - 0.033 ( \sim 25 & 80 km s ^ { -1 } ) , previously thought to be separate clouds along the same line-of-sight , are physically connected in position-velocity space via a third southern component around 50 km s ^ { -1 } .
Further position-velocity analysis of the surrounding region , using lower-resolution survey observations taken with the Mopra and ATCA telescopes , indicates that both molecular components in M0.20 - 0.033 are physically connected to the M0.10 - 0.08 molecular cloud , which is suggested to be located on stream 1 in the ( ) orbital model .
The morphology and kinematics of the molecular gas in M0.20 - 0.033 indicate that the two velocity components in M0.20 - 0.033 constitute an expanding shell .
Our observations suggest that the M0.20 - 0.033 expanding shell has an expansion velocity of 40 km s ^ { -1 } , with a systemic velocity of 53 km s ^ { -1 } , comparable to velocities detected in M0.10 - 0.08 .
The origin of the expanding shell is located near the Quintuplet cluster , suggesting that the energy and momentum output from this massive stellar cluster may have contributed to the expansion .