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 inflow ) and outflow rate ( ζ 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 * ) relation, and the gas mass ( M gas ) is derived using the recently established gas-scaling relations. With the growth curve, the net inflow rate κ is quantified at each cosmic epoch. At z  ∼ 1.3, κ is comparable with the SFR, whereas it rapidly decreases to ∼0.15 × SFR at z  = 0. We then constrain the average outflow rate ζ outflow of progenitor galaxies by modeling the evolution of their gas-phase metallicity. The best-fit ζ outflow is found to be (0.5–0.8) × SFR. Combining κ and ζ outflow , we finally investigate the evolution of ζ inflow since z  = 1.3. We find that ζ inflow rapidly decreases by ∼80% from z  = 1.3 to z  = 0.5. At z  < 0.5, ζ inflow continuously decreases but with a much lower decreasing rate. Implications of these findings on galaxy evolution are discussed.