Interstellar gas within $\sim 10$ pc of Sgr A$^*$

TL;DR

This paper constructs a detailed three-dimensional model of the interstellar gas within 10 parsecs of Sgr A*, integrating observational data to describe its spatial configuration and physical states.

Contribution

It provides the first comprehensive 3D representation of the interstellar gas components near Sgr A* based on extensive observational review.

Findings

Identified five main gas components around Sgr A*

Mapped the spatial distribution and physical states of these components

Quantified the volume and mass coverage of each gas component

Abstract

We seek to obtain a coherent and realistic three-dimensional picture of the interstellar gas out to about 10 pc of the dynamical center of our Galaxy, which is supposed to be at Sgr A$^*$. We review the existing observational studies on the different gaseous components that have been identified near Sgr A$^*$, and retain all the information relating to their spatial configuration and/or physical state. Based on the collected information, we propose a three-dimensional representation of the interstellar gas, which describes each component in terms of both its precise location and morphology and its thermodynamic properties. The interstellar gas near Sgr A$^*$ can represented by five basic components, which are, by order of increasing size: (1) a central cavity with roughly equal amounts of warm ionized and atomic gases, (2) a ring of mainly molecular gas, (3) a supernova remnant filled with hot ionized gas, (4) a radio halo of warm ionized gas and relativistic particles, and (5) a belt of massive molecular clouds. While the halo gas fills $\approx 80%$ of the studied volume, the molecular components enclose $\approx 98%$ of the interstellar mass.