Cosmic evolution of the galaxy's mass and luminosity functions by morphological type from multi-wavelength data in the CDF-South

Abstract

Aims. We constrain the evolution of the galaxy mass and luminosity functions from the analysis of (public) multi-wavelength data in the Chandra Deep Field South (CDFS) area, obtained from GOODS and other projects, including very deep high-resolution imaging by HST/ACS. Methods. Our reference catalogue of faint high-redshift galaxies, which we have thoroughly tested for completeness and reliability, comes from a deep (S 3.6 ≥ 1 µJy) image by IRAC on the Spitzer Observatory. These imaging data in the field are complemented by extensive optical spectroscopy by the ESO VLT/FORS2 and VIMOS spectrographs, while deep K-band VLT/ISAAC imaging is also used to derive further complementary statistical constraints and to assist the source identification and Spectral Energy Distribution (SED) analysis. We selected a highly reliable IRAC 3.6 µm sub-sample of 1478 galaxies with S 3.6 ≥ 10 µJy, 47% of which have spectroscopic redshift, while for the remaining objects we used both COMBO-17 data (Wolf et al. 2004, A&A, 421, 913) and the code Hyperz (Bolzonella et al. 2000, A&A, 363, 476) to estimate the photometric redshift. This very extensive dataset was exploited to assess evolutionary effects in the galaxy luminosity and stellar mass functions, while luminosity/density evolution is further constrained with the number counts and redshift distributions. The deep ACS imaging allows us to differentiate between these evolutionary paths by morphological type, which our simulations show to be reliable at least up to z ∼ 1.5 for the two main early- (E/S0) and late-type (Sp/Irr) classes.