%0 Journal Article
%T Exploring a new definition of the green valley and its implications
%+ Institut d'Astrophysique de Paris (IAP)
%A Angthopo, James
%A Ferreras, Ignacio
%A Silk, Joseph
%< avec comité de lecture
%@ 1745-3933
%J Monthly Notices of the Royal Astronomical Society: Letters
%I Oxford Journals
%V 488
%P L99-L103
%8 2019
%D 2019
%Z 1907.02093
%Z 2019MNRAS.488L..99A
%R 10.1093/mnrasl/slz106
%K galaxies: evolution
%K galaxies: formation
%K galaxies: interactions
%K galaxies: stellar content
%K Astrophysics - Astrophysics of Galaxies
%Z Sciences of the Universe [physics]
%Z Sciences of the Universe [physics]/Astrophysics [astro-ph]Journal articles
%X The distribution of galaxies on a colour-magnitude diagram reveals a bimodality, featuring a passively evolving red sequence and a star-forming blue cloud. The region between these two, the green valley (GV), represents a fundamental transition where quenching processes operate. We exploit an alternative definition of the GV using the 4000 Å break strength, an indicator that is more resilient than colour to dust attenuation. We compare and contrast our GV definition with the traditional one, based on dust-corrected colour, making use of data from the Sloan Digital Sky Survey. Our GV selection - that does not need a dust correction and thus does not carry the inherent systematics - reveals very similar trends regarding nebular activity (star formation, AGN, quiescence) to the standard dust-corrected 0.1(g - r). By use of high-SNR stacked spectra of the quiescent GV subsample, we derive the simple stellar population (SSP) age difference across the GV, a rough proxy of the quenching time-scale (Δt). We obtain an increasing trend with velocity dispersion (σ), from Δt ∼ 1.5 Gyr at σ = 100 km s-1, up to 3.5 Gyr at σ = 200 km s-1, followed by a rapid decrease in the most massive GV galaxies (Δt ∼ 1 Gyr at σ = 250 km s-1), suggesting two different modes of quenching, or the presence of an additional channel (rejuvenation).
%G English
%2 https://insu.hal.science/insu-03747920/document
%2 https://insu.hal.science/insu-03747920/file/slz106.pdf
%L insu-03747920
%U https://insu.hal.science/insu-03747920
%~ INSU
%~ CNRS
%~ IAP
%~ SORBONNE-UNIVERSITE
%~ SORBONNE-UNIV
%~ SU-SCIENCES
%~ SU-TI
%~ ALLIANCE-SU