The Supershell-Molecular Cloud Connection in the Milky Way and Beyond

TL;DR

This study provides observational evidence that supershells in the Milky Way and LMC contribute to molecular cloud formation, with detailed case studies showing increased molecularisation in supershell-affected regions.

Contribution

It offers the first quantitative observational evidence linking supershell activity to enhanced molecular cloud production in the Milky Way.

Findings

Supershells increase molecularisation in affected regions.

Supershells contribute approximately 10% to molecular cloud formation in the LMC.

Case studies demonstrate enhanced molecular cloud production due to supershells.

Abstract

The role of large-scale stellar feedback in the formation of molecular clouds has been investigated observationally by examining the relationship between HI and 12CO(J=1-0) in supershells. Detailed parsec-resolution case studies of two Milky Way supershells demonstrate an enhanced level of molecularisation over both objects, and hence provide the first quantitative observational evidence of increased molecular cloud production in volumes of space affected by supershell activity. Recent results on supergiant shells in the LMC suggest that while they do indeed help to organise the ISM into over-dense structures, their global contribution to molecular cloud formation is of the order of only ~10%.