# Relations Between Molecular Cloud Structure Sizes and Line Widths in the Large Magellanic Cloud

## TL;DR

This study investigates how the size-line width relation in molecular clouds within the Large Magellanic Cloud varies with star formation activity and mass surface density, highlighting the roles of gravity and feedback in cloud dynamics.

## Contribution

It provides new observational evidence linking line width variations to star formation activity and surface density in LMC molecular clouds, extending previous studies.

## Key findings

- Line width increases with star formation activity.
- Line width correlates with mass surface density.
- Both gravity and feedback influence cloud dynamics.

## Abstract

We present a comparative study of the size-line width relation for substructures within six molecular clouds in the Large Magellanic Cloud (LMC) mapped with the Atacama Large Millimeter/submillimeter Array (ALMA). Our sample extends our previous study, which compared a Planck detected cold cloud in the outskirts of the LMC with the 30 Doradus molecular cloud and found the typical line width for 1 pc radius structures to be 5 times larger in 30 Doradus. By observing clouds with intermediate levels of star formation activity, we find evidence that line width at a given size increases with increasing local and cloud-scale 8${\mu}$m intensity. At the same time, line width at a given size appears to independently correlate with measures of mass surface density. Our results suggest that both virial-like motions due to gravity and local energy injection by star formation feedback play important roles in determining intracloud dynamics.