Timescale of Stellar Feedback-Driven Turbulence in the ISM: A Deep Dive into UGC 4305

TL;DR

This study investigates the timescales over which stellar feedback influences turbulence in the interstellar medium of galaxy UGC 4305, revealing a significant correlation with past star formation activity 70-140 million years ago at local scales.

Contribution

It provides a spatially resolved analysis of turbulence and star formation history, highlighting the importance of local scales in understanding stellar feedback effects.

Findings

Strong correlation between HI turbulence and star formation 70-140 Myr ago.

No significant correlation at larger physical scales.

Turbulence driven by stellar feedback is primarily a local phenomenon.

Abstract

Understanding the interplay of stellar feedback and turbulence in the interstellar medium (ISM) is essential to modeling the evolution of galaxies. To determine the timescales over which stellar feedback drives turbulence in the ISM, we performed a spatially resolved, multi-wavelength study of the nearby star-forming dwarf galaxy UGC 4305 (aka Holmberg II). As indicators of turbulence on local scales (400 pc), we utilized ionized gas velocity dispersion derived from IFU H$\alpha$ observations and atomic gas velocity dispersion and energy surface densities derived from HI synthesis observations with the Very Large Array. These indicators of turbulence were tested against star formation histories over the past 560 Myr derived from Color-Magnitude Diagrams (CMD) using Spearman's rank correlation coefficient. The strongest correlation identified at the 400 pc scale is between measures of HI turbulence and star formation 70-140 Myr ago. We repeated our analysis of UGC 4305's current turbulence and past star formation activity on multiple physical scales ($\sim$560, and 800 pc) to determine if there are indications of changes in the correlation timescale with changes to the physical scale. No notable correlations were found at larger physical scales emphasizing the importance of analyzing star formation driven turbulence as a local phenomenon.