The red and blue galaxy populations in the GOODS field: evidence for an excess of red dwarfs

Abstract

We study the evolution of the galaxy population up to z\sim3 as a function of its colour properties. In particular, luminosity functions and luminosity densities have been derived as a function of redshift for the blue/late and red/early populations. We use data from the GOODS-MUSIC catalogue which have typical magnitude limits z<26 and Ks<23.5 for most of the sample. About 8% of the galaxies have spectroscopic redshifts; the remaining have well calibrated photometric redshifts derived from the extremely wide multi-wavelength coverage in 14 bands (from the U band to the Spitzer 8 μm band). We have derived a catalogue of galaxies complete in rest-frame B-band, which has been divided in two subsamples according to their rest-frame U-V colour (or derived specific star formation rate, SSFR) properties. We confirm a bimodality in the U-V colour and SSFR of the galaxy sample up to z\sim 3. This bimodality is used to compute the LFs of the blue/late and red/early subsamples. The LFs of the blue/late and total samples are well represented by steep Schechter functions evolving in luminosity with increasing redshifts. The volume density of the LFs of the red/early populations decreases with increasing redshift. The shape of the red/early LFs shows an excess of faint red dwarfs with respect to the extrapolation of a flat Schechter function and can be represented by the sum of two Schechter functions. Our model for galaxy formation in the hierarchical clustering scenario, which also includes external feedback due to a diffuse UV background, shows a general broad agreement with the LFs of both populations, the larger discrepancies being present at the faint end for the red population. Hints on the nature of the red dwarf population are given on the basis of their stellar mass and spatial distributions.

accepted for publication in A&A. Uses aa.cls, 13 pages, 11 figures

References in corpus (14)

• The Galaxy Mass Function up to z=4 in the GOODS-MUSIC sample: into the epoch of formation of massive galaxies
• The GOODS-MUSIC sample: a multicolour catalog of near-IR selected galaxies in the GOODS-South field
• The DEEP2 Galaxy Redshift Survey: Evolution of the Color-Density Relation at 0.4 < z < 1.35
• The evolution of the near-IR galaxy Luminosity Function and colour bimodality up to z ~ 2 from the UKIDSS Ultra Deep Survey Early Data Release
• The VIMOS VLT Deep Survey: The build-up of the colour-density relation
• The rest-frame optical luminosity functions of galaxies at 2<z<3.5
• Cosmic evolution of the galaxy mass and luminosity functions by morphological type from multi-wavelength data in the CDF-South
• A comparison among LBGs, DRGs and BzK galaxies: their contribution to the stellar mass density in the GOODS-MUSIC sample
• Physical properties of z~4 LBGs: differences between galaxies with and without Ly-alpha emission
• The Clustering Evolution of Distant Red Galaxies in the GOODS-MUSIC Sample
• The Color Magnitude Distribution of Field Galaxies to z~3: the evolution and modeling of the blue sequence
• The galaxy luminosity - size relation and selection biases in the Hubble Ultra Deep Field
• Semi-empirical analysis of Sloan Digital Sky Survey galaxies: IV. A nature via nurture scenario for galaxy evolution
• A new (2+1)D cluster finding algorithm based on photometric redshifts: large scale structure in the Chandra Deep Field South

Cited by in corpus (5)

• Faint AGNs at z>4 in the CANDELS GOODS-S field: looking for contributors to the reionization of the Universe
• The population of early-type galaxies: how it evolves with time and how it differs from passive and late-type galaxies
• The VANDELS survey: Discovery of massive overdensities of galaxies at z>2
• The ALHAMBRA survey : $B-$band luminosity function of quiescent and star-forming galaxies at $0.2\le z<1$ by PDF analysis
• Catalog-free modeling of galaxy types in deep images: Massive dimensional reduction with neural networks