The High-Density Ionized Gas in the Central Parsecs of the Galaxy

TL;DR

This study uses high-resolution submillimeter observations of H30α emission to analyze the high-density ionized gas near the Galactic Center, revealing black hole dominance with local dynamical deviations due to stellar winds and arm interactions.

Contribution

It provides detailed velocity field measurements of ionized gas in Sgr A West and compares them with a Keplerian model, highlighting the influence of stellar winds and arm interactions.

Findings

Supermassive black hole dominates gas dynamics.

Significant deviations from Keplerian motion detected.

Stellar winds and arm interactions influence local gas flows.

Abstract

We report the results from observations of H30$\alpha$ line emission in Sgr A West with the Submillimeter Array at a resolution of 2\arcsec and a field of view of about 40\arcsec. The H30$\alpha$ line is sensitive to the high-density ionized gas in the minispiral structure. We compare the velocity field obtained from H30$\alpha$ line emission to a Keplerian model, and our results suggest that the supermassive black hole at Sgr A* dominates the dynamics of the ionized gas. However, we also detect significant deviations from the Keplerian motion, which show that the impact of strong stellar winds from the massive stars along the ionized flows and the interaction between Northern and Eastern arms play significant roles in the local gas dynamics.