Determining the Timescale over Which Stellar Feedback Drives Turbulence in the ISM: A Study of four Nearby Dwarf Irregular Galaxies

TL;DR

This study investigates the timescales of stellar feedback-driven turbulence in the interstellar medium of four nearby dwarf galaxies, finding a significant correlation with star formation activity 100-200 million years ago.

Contribution

It provides new insights into the specific timescale (100-200 Myrs) over which stellar feedback influences gas turbulence in dwarf galaxies.

Findings

Strong correlation between HI turbulence and star formation 100-200 Myrs ago.

No significant correlation with ionized gas velocity dispersion.

Highlights the importance of historical star formation in driving ISM turbulence.

Abstract

Stellar feedback is fundamental to the modeling of galaxy evolution as it drives turbulence and outflows in galaxies. Understanding the timescales involved are critical for constraining the impact of stellar feedback on the interstellar medium (ISM). We analyzed the resolved star formation histories along with the spatial distribution and kinematics of the atomic and ionized gas of four nearby star-forming dwarf galaxies (NGC 4068, NGC 4163, NGC 6789, UGC 9128) to determine the timescales over which stellar feedback drives turbulence. The four galaxies are within 5 Mpc and have a range of properties including current star formation rates of 0.0005 to 0.01 M$_{\odot}$ yr$^{-1}$, log(M$_*$/M$_{\odot}$) between 7.2 and 8.2, and log(M$_{HI}$/M$_\odot$) between 7.2 and 8.3. Their Color-Magnitude Diagram (CMD) derived star formation histories over the past 500 Myrs were compared to their atomic and ionized gas velocity dispersion and HI energy surface densities as indicators of turbulence. The Spearman's rank correlation coefficient was used to identify any correlations between their current turbulence and their past star formation activity on local scales ($\sim$400 pc). The strongest correlation found was between the HI turbulence measures and the star formation rate 100-200 Myrs ago. This suggests a coupling between the star formation activity and atomic gas on this timescale. No strong correlation between the ionized gas velocity dispersion and the star formation activity between 5-500 Myrs ago was found. The sample and analysis are the foundation of a larger program aimed at understanding the timescales over which stellar feedback drives turbulence.