Starburst--driven galactic outflows

TL;DR

This paper introduces a combined radiation and thermal pressure model for starburst-driven galactic outflows, explaining observed wind speeds and properties in galaxies across different redshifts.

Contribution

It presents a novel model incorporating radiation pressure and supernova effects to better explain galactic outflows than previous thermal-only models.

Findings

Shell re-acceleration explains observed wind speeds.

Collision-induced shell fragmentation matches galaxy observations.

Model accounts for correlations in Lyman break galaxies.

Abstract

We propose a model of starburst--driven galactic outflows whose dynamics depends on both radiation and thermal pressure. Standard models of thermal pressure--driven winds fail to explain some key observations of outflows at low and high redshift galaxies. We discuss a scenario in which radiation pressure from massive stars in a stellar population drive a shell of gas and dust. Subsequent supernova (SN) explosions from the most massive stars in this population then drive stellar ejecta outward in a rarefied medium, making it collide with the radiation pressure driven shell. The collision imparts renewed momentum to the shell, and the resulting re-acceleration makes the shell Rayleigh-Taylor unstable, fragmenting the shell. We show that the speed of these ballistic fragments can explain some recently observed correlations in Lyman break galaxies between wind speed, reddening and star formation rate.