The Supershell-Molecular Cloud Connection: Large-Scale Stellar Feedback and the Formation of the Molecular ISM

TL;DR

This paper reviews how large-scale stellar feedback from OB clusters influences the formation of molecular clouds in the interstellar medium, highlighting recent models and observations that support feedback-driven cloud formation.

Contribution

It synthesizes current theoretical models and observational evidence for feedback-driven molecular cloud formation, emphasizing the role of large-scale flows and magnetic effects.

Findings

Strong evidence for feedback-driven molecular gas formation in the Milky Way and LMC.

Magneto-hydrodynamic simulations support the cloud formation process.

Observational and theoretical advances are aligning to clarify feedback's role.

Abstract

The accumulation, compression and cooling of the ambient interstellar medium (ISM) in large-scale flows powered by OB cluster feedback can drive the production of dense molecular clouds. We review the current state of the field, with a strong focus on the explicit modelling and observation of the neutral interstellar medium. Magneto-hydrodynamic simulations of colliding ISM flows provide a strong theoretical framework in which to view feedback-driven cloud formation, as do models of the gravitational fragmentation of expanding shells. Rapid theoretical developments are accompanied by growing body of observational work that provides good evidence for the formation of molecular gas via stellar feedback - both in the Milky Way and the Large Magellanic Cloud. The importance of stellar feedback compared to other major astrophysical drivers of dense gas formation remains to be investigated further, and will be an important target for future work.