MusE GAs FLOw and Wind (MEGAFLOW) XI. Scaling relations between outflows and host galaxy properties

Abstract

Absorption line spectroscopy using background quasars can provide strong constraints on galactic outflows. In this paper, we investigate possible scaling relations between outflow properties, namely outflow velocity \Vout, the mass ejection rate $\dot M_{\rm out}$, and the mass loading factor $\eta$ and the host galaxy properties, such as star formation rate (SFR), SFR surface density, redshift, and stellar mass using galactic outflows probed by background quasars from MEGAFLOW and other surveys. We find that $V_{\rm out}$ ($\eta$) is (anti-)correlated with SFR and SFR surface density. We extend the formalism of momentum-driven outflows of Heckman et al. to show that it applies not only to down the barrel studies but also to winds probed by background quasars, suggesting a possible universal wind formalism. Under this formalism, we find a clear distinction between ``strong'' and ``weak'' outflows where ``strong'' outflows seem to have tighter correlations with galaxy properties (SFR or galaxy stellar mass) than ``weak'' outflows.