Graduate student Laura Congreve Hunter and collaborators including IU faculty member Liese van Zee have published a study of the timescale over which stellar feedback drives turbulence in the interstellar medium. Star formation creates turbulence in a galaxy’s interstellar gas, and that turbulence can regular future star formation as well as create outflows that carry newly formed metals out of a galaxy and into the intergalactic medium. A correlation between current star formation activity and gas turbulence might be expected, but is not seen in some environments.
Hunter and colleagues have looked to see if an increase in gas turbulence might be delayed for some period after an episode of star formation by determining the star formation history in galaxies as well as the spatial distribution and kinematics of atomic and ionized gas. They looked specifically at four nearby, star-forming dwarf irregular galaxies, and determined star formation histories over the last 500 Myr from stellar color magnitude diagrams. Turbulence is measured from the velocity dispersions of the gas. They found that turbulence in the atomic gas in the interstellar medium increases some 100-200 million years after a period of star formation, but did not see a strong correlation between the velocity dispersion of ionized gas and star formation between 5-500 million years. The research is published in the Astronomical Journal.
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