Outflow velocity as a function of host galaxy properties. Top left: V_out as a function of SFR for MEGAFLOW and SIMPLE as well as observations from all the samples used in this study. The dashed black line shows a fit (log V = (0.35 ± 0.06)log(SFR)+(1.56 ± 0.13)) from Martin (2005). The errors on the Heckman et al. (2015) observations are 0.2 dex for SFR and 0.05 dex for V_out. Top middle: V_out as a function of Σ_SFR for the same surveys as in the left panel. Top right: V_out as a function of S_0.5. The red dot-dashed line shows a fit from H16. In these three panels, red (blue) observations correspond to starbursts (SFGs) for P23 or strong (weak) outflows for MEGAFLOW, M19, and H15. Bottom: outflow velocity normalized by the galaxy circular velocity as a function of the specific SFR (SFR/M_*), SFR surface density (ΣSFR), and a combination of specific SFR and Σ_SFR found in H15 (from left to right).