http://arxiv.org/abs/1802.07628
We investigate the connection between environment and the different quenching channels that galaxies are prone to follow in the rest-frame NUVrK (i.e., NUV-r vs. r-K) colour diagram, as identified by Moutard et al. (2016b). Namely, the (fast) quenching channel followed by ($young$) low-mass galaxies and the (slow) quenching channel followed by ($old$) high-mass ones. We make use of the >22 deg$^2$ covered the VIPERS Multi-Lambda Survey (VIPERS-MLS) to select a galaxy sample complete down to stellar masses of $M_* > 10^{9.4} M_\odot$ at $z < 0.65$ ($M_* > 10^{8.8} M_\odot$ at $z < 0.5$) and including 33,500 (43,000) quiescent galaxies properly selected at $0.2 < z < 0.65$, while being characterized by reliable photometric redshifts ($\sigma_{\delta z/(1+z)} \leq 0.04$) that we use to measure galaxy local densities. We find that (1) the quiescence of low-mass [$M_* \leq 10^{9.7} M_\odot$] galaxies requires a strong increase of the local density, which confirms the lead role played by environment in their fast quenching and, therefore, confirms that the low-mass upturn observed in the stellar mass function of quiescent galaxies is due to $environmental$ $quenching$. We also observe that (2) the reservoir of low-mass galaxies prone to environmental quenching has grown between $z \sim 0.6$ and $ z \sim 0.4$ whilst the share of low-mass galaxies in the quiescent population may have simultaneously increased, which may be consistent with a rising importance of $environmental$ $quenching$ with cosmic time, compared to $mass$ $quenching$. We finally discuss the composite picture of such environmental quenching of low-mass galaxies and, in particular, how this picture may be consistent with a $delayed$-$then$-$rapid$ quenching scenario.
T. Moutard, M. Sawicki, S. Arnouts, et. al.
Thu, 22 Feb 18
39/60
Comments: 14 pages, 5 figures, submitted to MNRAS; revised version