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

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, multiwavelength study of the nearby star-forming dwarf galaxy UGC 4305. As indicators of turbulence on local scales (400 pc), we utilized ionized gas velocity dispersion derived from IFU H α observations and atomic gas velocity dispersion and energy surface densities derived from H i 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 using Spearman’s rank correlation coefficient. The strongest correlation identified at the 400 pc scale is between measures of H i 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 (∼560 and 800 pc) to determine whether 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.

Keywords

• Interstellar medium
• Dwarf galaxies
• Extragalactic astronomy
• Radio astronomy
• Interstellar atomic gas
• Optical astronomy