Science with an ngVLA: Molecular Clouds in Galaxies

TL;DR

The proposed ngVLA will significantly advance understanding of molecular cloud formation, properties, and destruction across galaxies by enabling comprehensive surveys and detailed studies of cloud substructures and kinematics.

Contribution

This paper highlights how the ngVLA's thermal line imaging capabilities will enable unprecedented surveys and detailed analyses of molecular clouds in diverse galactic environments.

Findings

Enables rapid surveys of molecular cloud properties across nearby galaxies.

Allows detailed studies of cloud substructure and internal physics.

Provides new constraints on cloud formation and star formation processes.

Abstract

Stars form in cold clouds of predominantly molecular (H2) gas. We are just beginning to understand how the formation, properties, and destruction of these clouds varies across the universe. In this chapter, we describe how the thermal line imaging capabilities of the proposed next generation Very Large Array (ngVLA) could make major contributions to this field. Looking at CO emission, the proposed ngVLA would be able to quickly survey the bulk properties of molecular clouds across the whole nearby galaxy population. This includes many unique very nearby northern targets (e.g., Andromeda) inaccessible to ALMA. Such surveys offer a main observational constraint on the formation, destruction, lifetime, and star formation properties of clouds. Targeting specific regions, the ngVLA will also be able to heavily resolve clouds in the nearest galaxies. This will allow detailed studies of the substructure and kinematics --- and so the internal physics --- of clouds across different chemical and dynamical environments.