The Life and Times of Giant Molecular Clouds

TL;DR

This paper reviews recent advances in understanding giant molecular clouds (GMCs), focusing on their formation, evolution, and destruction, driven by high-resolution observations and simulations that explore their dependence on galactic environments.

Contribution

It synthesizes recent observational and simulation studies to provide a comprehensive overview of GMC properties, their environmental influences, and open questions in the field.

Findings

GMC properties vary with galactic environment.

High-resolution observations have enabled detailed GMC studies.

Simulations increasingly incorporate galactic-scale effects.

Abstract

Giant molecular clouds (GMCs) are the sites of star formation and stellar feedback in galaxies. Their properties set the initial conditions for star formation and their lifecycles determine how feedback regulates galaxy evolution. In recent years, the advent of high-resolution telescopes has enabled systematic GMC-scale studies of the molecular interstellar medium in nearby galaxies, now covering a wide range of physical conditions and allowing for the first studies of how GMC properties depend on galactic environment. These observational developments have been accompanied by numerical simulations of improving resolution that are increasingly accurately accounting for the effects of the galactic-scale environment on GMCs, while simultaneously improving the treatment of the small-scale processes of star-formation and stellar feedback within them. The combination of these recent developments has greatly improved our understanding of the formation, evolution, and destruction of GMCs. We review the current state of the field, highlight current open questions, and discuss promising avenues for future studies.