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

摘要

We constrain the evolution of the galaxy mass and luminosity functions fromthe analysis of (public) multi-wavelength data in the Chandra Deep Field South(CDFS) area, obtained from the GOODS and other projects, and including verydeep high-resolution imaging by HST/ACS. Our reference catalogue of fainthigh-redshift galaxies, which we have thoroughly tested for completeness andreliability, comes from a deep (S(3.6micron)>1 microJy) image by IRAC on theSpitzer Observatory. These imaging data in the field are complemented withextensive optical spectroscopy by the ESO VLT/FORS2 and VIMOS spectrographs,while deep K-band VLT/ISAAC imaging is also used to derive furthercomplementary statistical constraints and to assist the source identificationand SED analysis. We have selected a highly reliable IRAC 3.6micron sub-sampleof 1478 galaxies with S(3.6)>10microJy, 47% of which have spectroscopicredshift, while for the remaining objects both COMBO-17 and Hyperz are used toestimate the photometric redshift. This very extensive dataset is exploited toassess evolutionary effects in the galaxy luminosity and stellar massfunctions, while luminosity/density evolution is further constrained with thenumber counts and redshift distributions. The deep ACS imaging allows us todifferentiate these evolutionary paths by morphological type, which oursimulations show to be reliable at least up to z=1.5 for the two main early-(E/S0) and late-type (Sp/Irr) classes. These data, as well as our directestimate of the stellar mass function above M=10^(10)M_sun for the spheroidalsubclass, consistently evidence a progressive dearth of such objects to occurstarting at z=0.7, paralleled by an increase in luminosity. (abridged)