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

TL;DR

This study uses high-frequency VLA observations to reveal that the molecular cloud M0.20-0.033 near the Galactic Center is an expanding shell likely driven by the Quintuplet cluster, connecting multiple velocity components and molecular clouds.

Contribution

It provides the first detailed analysis showing M0.20-0.033 as an expanding shell linked to the Quintuplet cluster, integrating multi-telescope data and position-velocity analysis.

Findings

M0.20-0.033 consists of three connected velocity components.

The shell expands at approximately 40 km/s.

The shell's origin is near the Quintuplet cluster.

Abstract

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 (~25 & 80 km/s), 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. 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. (2015) 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, with a systemic velocity of 53 km/s, 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.