Evolution of Gas Flows along the Starburst to Post-Starburst to Quiescent Galaxy Sequence

Understand

We measure velocity offsets in the NaI $\lambda\lambda5890, 5896$ (Na D) interstellar medium absorption lines to track how neutral galactic winds change as their host galaxies evolve.

• Our sample of $\sim$80,000 SDSS spectra at $0.010 < z < 0.325$ includes starburst, post-starburst, and quiescent galaxies, forming an evolutionary sequence of declining star formation rate (SFR).
• We detect bulk flows across this sequence, mostly at higher host stellar masses($log(M_{\star}/M_{\odot})>10$).
• Along this sequence, the fraction of outflows decreases ($76\pm2\%$ to $65\pm4\%$ to a 3$\sigma$ upper limit of $34\%$), and the mean velocity offset changes from outflowing to inflowing ($-84.6\pm5.9$ to $-71.6\pm11.4$ to $76.6\pm2.3\,km\,s^{-1}$).