Discovery of the Pigtail Molecular Cloud in the Galactic Center

TL;DR

This paper reports the discovery of a unique helical molecular cloud in the Galactic Center, providing insights into magnetic interactions and cloud dynamics in the central molecular zone.

Contribution

It presents the first detailed observation and analysis of a helical 'pigtail' molecular cloud, expanding understanding of magnetic structures in the Galactic Center.

Findings

Discovery of the third helical molecular cloud in the Galactic Center

The pigtail cloud has higher temperature/density than typical CMZ clouds

Evidence of a magnetic tube interaction model for cloud formation

Abstract

This paper reports the discovery of a helical molecular cloud in the central molecular zone (CMZ) of our Galaxy. This "pigtail" molecular cloud appears at (l, b, V_LSR) ~ (-0.7deg, +0.0deg, -70 to -30 km/s), with a spatial size of ~ (20 pc)^2 and a mass of (2-6) 10^5 solar masses. This is the third helical gaseous nebula found in the Galactic center region to date. Line intensity ratios indicate that the pigtail molecular cloud has slightly higher temperature and/or density than the other normal clouds in the CMZ. We also found a high-velocity wing emission near the footpoint of this cloud. We propose a formation model of the pigtail molecular cloud. It might be associated with a magnetic tube that is twisted and coiled because of the interaction between clouds in the innermost x_1 orbit and ones in the outermost x_2 orbit.