A Search for correlations between turbulence and star formation in THINGS galaxies

TL;DR

This study investigates the relationship between star formation activity and interstellar turbulence in THINGS galaxies, finding limited local impact of feedback energy on HI gas motion and suggesting other mechanisms dominate energy distribution.

Contribution

It provides the first detailed analysis of HI kinetic energy and velocity dispersion in relation to star formation regions across multiple galaxies, highlighting the limited local effect of feedback.

Findings

Most feedback energy does not increase local HI motion.

Feedback likely disrupts molecular clouds rather than HI gas.

Energy from star formation may spread over larger regions or come from other sources.

Abstract

The spatial range for feedback from star formation varies from molecular cloud disruption on parsec scales to supershells and disk blowout on kiloparsec scales. The relative amounts of energy and momentum given to these scales is important for understanding the termination of star formation in any one region and the origin of interstellar turbulence and disk stability in galaxies as a whole. Here we measure for eleven THINGS galaxies the excess kinetic energy, velocity dispersion and surface density of HI gas associated with regions of excess star formation, where the excess is determined from the difference between the observed local value and the azimuthal average. We find small decreases in the excess kinetic energy and velocity dispersion in regions of excess star formation rate density, suggesting that most of the feedback energy does not go into local HI motion. Most likely it disrupts molecular clouds and dissipates rapidly at high gas density. Some could also be distributed over larger regions, filling in spaces between the peaks of star formation and contributing to other energy sources from self-gravity and spiral arm shocks.