The inflow and outflow rate evolution of local Milky Way-mass star-forming galaxies since z=1.3

Abstract

We study the gas inflow rate ($ζ_{\rm inflow}$) and outflow rate ($ζ_{\rm outflow}$) evolution of local Milky Way-mass star-forming galaxies (SFGs) since $z=1.3$. The stellar mass growth history of Milky Way-mass progenitor SFGs is inferred from the evolution of the star formation rate (SFR)$-$stellar mass ($M_{\ast}$) relation, and the gas mass ($M_{\rm gas}$) is derived using the recently established gas scaling relations. With the $M_{\ast}+M_{\rm gas}$ growth curve, the net inflow rate $κ$ is quantified at each cosmic epoch. At $z\sim 1.3$, $κ$ is comparable with the SFR, whereas it rapidly decreases to $\sim 0.15\times$SFR at $z=0$. We then constrain the average outflow rate $ζ_{\rm outflow}$ of progenitor galaxies by modeling the evolution of their gas-phase metallicity. The best-fit $ζ_{\rm outflow}$ is found to be $(0.5-0.8)\times$SFR. Combining $κ$ and $ζ_{\rm outflow}$, we finally investigate the evolution of $ζ_{\rm inflow}$ since $z=1.3$. We find that $ζ_{\rm inflow}$ rapidly decreases by $\sim$80\% from $z=1.3$ to $z=0.5$. At $z<0.5$, $ζ_{\rm inflow}$ continuously decreases but with a much lower decreasing rate. Implications of these findings on galaxy evolution are discussed.