Parsec-scale SiO emission in the Galactic Center

TL;DR

This study uses single dish SiO (1-0) observations with the Green Bank Telescope to explore small-scale gas kinematics in the Galactic Center's central 5 parsecs, revealing unique SiO emission in the NE Arm of the circumnuclear disk.

Contribution

First single dish SiO (1-0) observations of the central 5 pc around Sgr A* highlighting small-scale gas dynamics and identifying the NE Arm as a potential collision or star formation site.

Findings

High SiO emission in the NE Arm suggests active cloud interactions or star formation.

Most SiO traces are associated with the southern streamer and Sgr A East, not the CND.

The NE Arm shows unique SiO emission indicating dynamic processes.

Abstract

The central 5 parsecs of our Galactic Center is rich in various molecular tracers. The region is observed to be hot, highly ionized, and volatile, resulting in complex chemistry and kinematics. Countless molecular observations of the central region orbiting the central super-massive black hole Sgr A* have revealed a stable grouping of clouds with a disk-like structure known as the circumnuclear disk (CND) orbiting Sgr A* between 1.5 and 3 pc. The CND houses the densest population of gas outside the ionized streams in the minispiral falling onto Sgr A*. However, the small-scale kinematics of the clouds and gas are poorly understood in this region. In this paper, we report single dish SiO (1-0) observations of the central 5 pc surrounding Sgr A* taken with the Green Bank Telescope. Most of the SiO (1-0) traces the southern streamer and Sgr A East-neither of which are associated with the CND. However, one region in the CND, known as the NE Arm, shows high-intensity SiO emission unlike in the rest of the CND, indicating the NE Arm as a candidate region of either cloud-cloud collision or early star formation. Further high resolution observations of the region are needed to distinguish between the two scenarios.