We explore the evolution of the colour–magnitude relation (CMR) and luminosity function (LF) at 0.4 < z < 1.3 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) using ∼45 000 galaxies with precise spectroscopic redshifts down to i′AB < 22.5 over ∼10.32 deg2 in two fields.Fromz=0.5toz=1.3theLFandCMRarewelldefinedfordifferentgalaxypopulationsandMB∗ evolvesby∼1.04(1.09)±0.06(0.10)mag for the total (red) galaxy sample. We compare different criteria for selecting early-type galaxies: (1) a fixed cut in rest-frame (U − V) colours, (2) an evolving cut in (U − V) colours, (3) a rest-frame (NUV − r′) − (r′ − K) colour selection, and (4) a spectral-energy-distribution classification. The completeness and contamination varies for the different methods and with redshift, but regardless of the method we measure a consistent evolution of the red-sequence (RS). Between 0.4 < z < 1.3 we find a moderate evolution of the RS intercept of Δ(U − V) = 0.28 ± 0.14 mag, favouring exponentially declining star formation (SF) histories with SF truncation at 1.7 ≤ z ≤ 2.3. Together with the rise in the number density of red galaxies by 0.64 dex since z = 1, this suggests a rapid build-up of massive galaxies (M⋆ > 1011 M⊙) and expeditious RS formation over a short period of ∼1.5 Gyr starting before z = 1. This is supported by the detection of ongoing SF in early-type galaxies at 0.9 < z < 1.0, in contrast with the quiescent red stellar populations of early-type galaxies at 0.5 < z < 0.6. There is an increase in the observed CMR scatter with redshift, which is two times larger than observed in galaxy clusters and at variance with theoretical model predictions. We discuss possible physical mechanisms that support the observed evolution of the red galaxy population. Our findings point out that massive galaxies have experienced a sharp SF quenching at z ∼ 1 with only limited additional merging. In contrast, less-massive galaxies experience a mix of SF truncation and minor mergers which build-up the low- and intermediate-mass end of the CMR.
A. Fritz, M. Scodeggio, O. Ilbert, M. Bolzonella, I. Davidzon, J. Coupon, et al. (2014). The VIMOS Public Extragalactic Redshift Survey (VIPERS): A quiescent formation of massive red-sequence galaxies over the past 9 Gyr. ASTRONOMY & ASTROPHYSICS, 563, A92-A92 [10.1051/0004-6361/201322379].
The VIMOS Public Extragalactic Redshift Survey (VIPERS): A quiescent formation of massive red-sequence galaxies over the past 9 Gyr
DAVIDZON, IARY;CUCCIATI, OLGA;MARULLI, FEDERICO;MOSCARDINI, LAURO;
2014
Abstract
We explore the evolution of the colour–magnitude relation (CMR) and luminosity function (LF) at 0.4 < z < 1.3 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) using ∼45 000 galaxies with precise spectroscopic redshifts down to i′AB < 22.5 over ∼10.32 deg2 in two fields.Fromz=0.5toz=1.3theLFandCMRarewelldefinedfordifferentgalaxypopulationsandMB∗ evolvesby∼1.04(1.09)±0.06(0.10)mag for the total (red) galaxy sample. We compare different criteria for selecting early-type galaxies: (1) a fixed cut in rest-frame (U − V) colours, (2) an evolving cut in (U − V) colours, (3) a rest-frame (NUV − r′) − (r′ − K) colour selection, and (4) a spectral-energy-distribution classification. The completeness and contamination varies for the different methods and with redshift, but regardless of the method we measure a consistent evolution of the red-sequence (RS). Between 0.4 < z < 1.3 we find a moderate evolution of the RS intercept of Δ(U − V) = 0.28 ± 0.14 mag, favouring exponentially declining star formation (SF) histories with SF truncation at 1.7 ≤ z ≤ 2.3. Together with the rise in the number density of red galaxies by 0.64 dex since z = 1, this suggests a rapid build-up of massive galaxies (M⋆ > 1011 M⊙) and expeditious RS formation over a short period of ∼1.5 Gyr starting before z = 1. This is supported by the detection of ongoing SF in early-type galaxies at 0.9 < z < 1.0, in contrast with the quiescent red stellar populations of early-type galaxies at 0.5 < z < 0.6. There is an increase in the observed CMR scatter with redshift, which is two times larger than observed in galaxy clusters and at variance with theoretical model predictions. We discuss possible physical mechanisms that support the observed evolution of the red galaxy population. Our findings point out that massive galaxies have experienced a sharp SF quenching at z ∼ 1 with only limited additional merging. In contrast, less-massive galaxies experience a mix of SF truncation and minor mergers which build-up the low- and intermediate-mass end of the CMR.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
