DUVET: sub-kiloparsec resolved star formation driven outflows in a sample of local starbursting disk galaxies

TL;DR

This study uses high-resolution observations to analyze star formation-driven outflows in local starburst galaxies, revealing strong correlations with local star formation and stellar mass densities, and suggesting supernovae as the driving mechanism.

Contribution

First resolved measurement of outflow properties in local starburst galaxies, establishing new scaling relations with local surface densities and providing insights into outflow driving mechanisms.

Findings

Outflow mass flux strongly correlates with SFR and stellar mass surface densities.

Outflows are common above a specific ratio of SFR to stellar mass surface density.

Outflows are driven by supernovae, requiring more energy in denser environments.

Abstract

We measure resolved (kiloparsec-scale) outflow properties in a sample of 10 starburst galaxies from the DUVET (Deep near-UV observations of Entrained gas in Turbulent galaxies) sample, using Keck/KCWI observations of H$\beta$ and [OIII]~$\lambda$5007. We measure $\sim460$ lines-of-sight that contain outflows, and use these to study scaling relationships of outflow velocity ($v_{\rm out}$), mass-loading factor ($\eta$; mass outflow rate per SFR) and mass flux ($\dot{\Sigma}_{\rm out}$; mass outflow rate per area) with co-located SFR surface density ($\Sigma_{\rm SFR}$) and stellar mass surface density ($\Sigma_{\ast}$). We find strong, positive correlations of $\dot{\Sigma}_{\rm out} \propto \Sigma_{\rm SFR}^{1.2}$ and $\dot{\Sigma}_{\rm out} \propto \Sigma_{\ast}^{1.5}$. We also find shallow correlations between $v_{\rm out}$ and both $\Sigma_{\rm SFR}$ and $\Sigma_{\ast}$. Our resolved observations do not suggest a threshold in outflows with $\Sigma_{\rm SFR}$, but rather we find that the local specific SFR ($\Sigma_{\rm SFR}/\Sigma_\ast$) is a better predictor of where outflows are detected. We find that outflows are very common above $\Sigma_{\rm SFR}/\Sigma_\ast\gtrsim 0.1$~Gyr$^{-1}$ and rare below this value. We argue that our results are consistent with a picture in which outflows are driven by supernovae, and require more significant injected energy in higher mass surface density environments to overcome local gravity. The correlations we present here provide a statistically robust, direct comparison for simulations and higher redshift results from JWST.