# What drives the velocity dispersion of ionized gas in star-forming galaxies?

## TL;DR

This study investigates what influences the velocity dispersion of ionized gas in star-forming galaxies, finding correlations with star formation activity but highlighting that existing models do not fully explain the observations.

## Contribution

It provides a comprehensive analysis of velocity dispersion in a large galaxy sample and compares results with theoretical models, revealing limitations of current explanations.

## Key findings

- Velocity dispersion correlates strongly with SFR and SFR surface density.
- Moderate correlation between velocity dispersion and stellar mass.
- Star formation feedback and gravitational instability alone cannot fully explain the observed relationships.

## Abstract

We analyze the intrinsic velocity dispersion properties of 648 star-forming galaxies observed by the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, to explore the relation of intrinsic gas velocity dispersions with star formation rates (SFRs), SFR surface densities ($\rm{\Sigma_{SFR}}$), stellar masses and stellar mass surface densities ($\rm{\Sigma_{*}}$). By combining with high z galaxies, we found that there is a good correlation between the velocity dispersion and the SFR as well as $\rm{\Sigma_{SFR}}$. But the correlation between the velocity dispersion and the stellar mass as well as $\rm{\Sigma_{*}}$ is moderate. By comparing our results with predictions of theoretical models, we found that the energy feedback from star formation processes alone and the gravitational instability alone can not fully explain simultaneously the observed velocity-dispersion/SFR and velocity-dispersion/$\rm{\Sigma_{SFR}}$ relationships.