The SEDIGISM survey: Molecular cloud morphology. II. Integrated source properties

TL;DR

This study analyzes the properties of molecular clouds in the Milky Way using high-resolution $^{13}$CO maps from the SEDIGISM survey, revealing how cloud morphology correlates with physical characteristics and their placement on scaling relations.

Contribution

It links cloud morphologies to their physical properties and provides insights into the formation and evolution mechanisms of different cloud types.

Findings

Ring-like clouds have higher masses, sizes, and velocity dispersions.

Morphology correlates with virial parameter, indicating different stability states.

Physical mechanisms like stellar feedback influence cloud structures.

Abstract

The Structure, Excitation, and Dynamics of the Inner Galactic InterStellar Medium (SEDIGISM) survey has produced high (spatial and spectral) resolution $^{13}$CO (2-1) maps of the Milky Way. It has allowed us to investigate the molecular interstellar medium in the inner Galaxy at an unprecedented level of detail and characterise it into molecular clouds. In a previous paper, we have classified the SEDIGISM clouds into four morphologies. However, how the properties of the clouds vary for these four morphologies is not well understood. Here, we use the morphological classification of SEDIGISM clouds to find connections between the cloud morphologies, their integrated properties, and their location on scaling relation diagrams. We observe that ring-like clouds show the most peculiar properties, having, on average, higher masses, sizes, aspect ratios and velocity dispersions compared to other morphologies. We speculate that this is related to the physical mechanisms that regulate their formation and evolution, for example, turbulence from stellar feedback can often results in the creation of bubble-like structures. We also see a trend of morphology with virial parameter whereby ring-like, elongated, clumpy and concentrated clouds have virial parameters in a decreasing order. Our findings provide a foundation for a better understanding of the molecular cloud behaviour based on their measurable properties.