On the onset of galactic winds in quiescent star forming galaxies

TL;DR

This study models supernova feedback in disk galaxies, revealing that galactic winds mainly occur in low-mass systems due to ram pressure effects, with implications for galaxy evolution and metal enrichment.

Contribution

It introduces a detailed simulation framework incorporating infalling gas, halo properties, and supernova feedback to analyze wind formation in quiescent galaxies, highlighting the role of ram pressure.

Findings

Galactic winds occur only in low-mass galaxies due to ram pressure.

Feedback efficiency is very low, around 1%.

Massive galaxies exhibit galactic fountains rather than winds.

Abstract

We studied the effect of supernovae feedback on a disk galaxy, taking into account the impact of infalling gas on both the star formation history and the corresponding outflow structure, the apparition of a supernovae-driven wind being highly sensitive to the halo mass, the galaxy spin and the star formation efficiency. We model our galaxies as cooling and collapsing NFW spheres. The dark matter component is modelled as a static external potential, while the baryon component is described by the Euler equations using the AMR code RAMSES. Metal-dependent cooling and supernovae-heating are also implemented using state-of-the-art recipes coming from cosmological simulations. We allow for 3 parameters to vary: the halo circular velocity, the spin parameter and the star formation efficiency. We found that the ram pressure of infalling material is the key factor limiting the apparition of galactic winds. We obtain a very low feedback efficiency, with supernovae to wind energy conversion factor around one percent, so that only low cicrular velocity galaxies give rise to strong winds. For massive galaxies, we obtain a galatic fountain, for which we discuss the observational properties. We conclude that for quiescent isolated galaxies, galactic winds appear only in very low mass systems. Although that can quite efficiently enrich the IGM with metals, they don't carry away enough cold material to solve the overcooling problem.