2019ApJ...873..122D

We investigate the relationship between star formation activity and outflow properties on kiloparsec scales in a sample of 28 star-forming galaxies at z ∼ 2-2.6, using adaptive optics assisted integral field observations from SINFONI on the Very Large Telescope. The narrow and broad components of the Hα emission are used to simultaneously determine the local star formation rate surface density (Σ_SFR), and the outflow velocity v_out and mass outflow rate {dot}M_out, respectively. We find clear evidence for faster outflows with larger mass loading factors at higher Σ_SFR. The outflow velocities scale as v_out ∝ Σ_SFR^0.34±0.10, which suggests that the outflows may be driven by a combination of mechanical energy released by supernova explosions and stellar winds, as well as radiation pressure acting on dust grains. The majority of the outflowing material does not have sufficient velocity to escape from the galaxy halos, but will likely be re-accreted and contribute to the chemical enrichment of the galaxies. In the highest Σ_SFR regions the outflow component contains an average of ∼45% of the Hα flux, while in the lower Σ_SFR regions only ∼10% of the Hα flux is associated with outflows. The mass loading factor, η = {dot}M_out/SFR, is positively correlated with Σ_SFR but is relatively low even at the highest Σ_SFR: η <= 0.5 x (380 cm^–3/n_e). This may be in tension with the η >= 1 required by cosmological simulations, unless a significant fraction of the outflowing mass is in other gas phases and has sufficient velocity to escape the galaxy halos.