Observed Timescales of Stellar Feedback in Star-Forming, Low-Mass Galaxies

TL;DR

This study investigates the timescales of atomic gas turbulence in low-mass star-forming galaxies, revealing a significant correlation with star formation activity over 100 million years ago, which sheds light on turbulence decay in the ISM.

Contribution

It combines star formation histories with gas kinematics at high spatial resolution to identify the timescale coupling between star formation and atomic gas turbulence in low-mass galaxies.

Findings

Atomic hydrogen turbulence correlates with star formation activity over 100 Myr ago.

No strong correlation between ionized gas velocity dispersion and recent star formation.

Differences observed between local and global turbulence properties.

Abstract

Understanding the timescales of atomic gas turbulence is crucial to understanding the interplay between star formation and the interstellar medium (ISM). To investigate the timescales of turbulence low-mass galaxies ($10^{6.8}<M_\odot<10^9$), this study combines temporally resolved star formation histories (SFHs) -- derived from color-magnitude diagrams -- with kinematic data of the atomic and ionized hydrogen in a large sample of nearby, star-forming, low-mass galaxies. To best understand the timescales involved, SFHs and gas kinematics were analyzed in 400$\times$400 parsec regions to capture the local impacts of star formation. No strong correlation was found between the ionized gas velocity dispersion and the star formation activity over the past 5-500 Myr. In contrast, a consistent and significant correlation between the atomic hydrogen turbulence measures and the star formation activity t$\geq$100 Myr ago was identified. This correlation suggests the star formation activity and atomic gas are coupled on this timescale. This connection between star-formation activity $>$100 Myr ago, and the HI turbulence properties, may be related to the time scales over which turbulence decays in the ISM. Additionally, the results demonstrate a possible difference in the global and local turbulence properties of low-mass galaxies.