http://arxiv.org/abs/1811.09283
Star-forming galaxies can in principle be transformed into passive systems by a multitude of processes that quench star formation, such as the halting of gas accretion or the rapid removal of gas in AGN-driven outflows. However, it remains unclear which processes are the most significant, primary drivers of the SF-passive bimodality. We address this key issue in galaxy evolution by studying the chemical properties of 80,000 local galaxies in SDSS DR7. In order to distinguish between different quenching mechanisms, we analyse the systematic difference in mass-weighted stellar metallicity between star-forming, green valley and passive galaxies. Our analysis reveals that the star-forming progenitors of massive ($M_* \sim 10^{11}~\mathrm{M_{\odot}}$) local passive galaxies quenched primarily through starvation over a time-scale of 2 Gyr, before any future star formation was abruptly halted by an ejective or heating mode. We find that outflows played a minor role in quenching the progenitors of massive galaxies, but were of increasing importance in quenching the progenitors of low-mass ($M_* < 10^{10}~\mathrm{M_{\odot}}$) passive galaxies over a typical time-scale of 5 Gyr. Furthermore, our analysis reveals that local green valley galaxies have typically been quenching through starvation for 3.5 Gyr, indicating that galaxies in the local Universe quench more slowly than their counterparts at higher redshift. Finally, we find that the quenching of central galaxies is independent of the environment. In contrast, we find that environmental effects contributed to the starvation of low-mass satellite galaxies in very dense environments.
J. Trussler, R. Maiolino, C. Maraston, et. al.
Mon, 26 Nov 18
82/100
Comments: 28 pages, 20 figures, 1 table. Submitted to MNRAS
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