M0.20-0.033: An Expanding Molecular Shell in the Galactic Center Radio Arc

We present high-frequency Karl G. Jansky Very Large Array (VLA) continuum and spectral line (NH3, 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. (similar to 25 and 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 Kruijssen et al. 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.