Cloud-cloud collisions in the common foot point of molecular loops 1 and 2 in the Galactic Center

TL;DR

This study provides the first evidence of cloud-cloud collisions in the Galactic Center's molecular loops, revealing their role in triggering star formation in a region with dense molecular gas.

Contribution

It introduces a new methodology for identifying cloud-cloud collisions in the Galactic Center and presents the first systematic evidence of such events in the region.

Findings

Detected clear signatures of cloud-cloud collisions in the Galactic Center.

Estimated collision timescales of 10^5 to 10^6 years.

Discussed the role of CCCs in triggering star formation in the GC.

Abstract

Recent large-area, deep CO surveys in the Galactic disk have revealed the formation of ~50 high-mass stars or clusters triggered by cloud-cloud collisions (CCCs). Although the Galactic Center (GC) -- which contains the highest volume density of molecular gas -- is the most favorable place for cloud collisions, systematic studies of CCCs in that region are still untouched. Here we report for the first time evidence of CCCs in the common foot point of molecular loops 1 and 2 in the GC. We have investigated the distribution of molecular gas toward the foot point by using a methodology for identifying CCCs, and we have discovered clear signatures of CCCs. Using the estimated displacements and relative velocities of the clouds, we find the elapsed time since the beginnings of the collisions to be 105-6 yr. We consider possible origins for previously reported peculiar velocity features in the foot point and discuss star formation triggered by CCCs in the GC.