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