The VIPERS Multi-Lambda Survey

II. Diving with massive galaxies in 22 square degrees since z = 1.5

¹ Aix Marseille Université, CNRS, LAM – Laboratoire d’Astrophysique de Marseille, 38 rue F. Joliot-Curie, 13388 Marseille, France
e-mail: thibaud.moutard@lam.fr
² Astronomical Observatory of the University of Geneva, ch. d’Ecogia16, 1290 Versoix, Switzerland
³ INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
⁴ INAF – Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate/via Brera 28, 20122 Milano, Italy
⁵ Sorbonne Université, UPMC Univ. Paris 06, et CNRS, UMR 7095, IAP, 98bis Bd Arago, 75014 Paris, France
⁶ Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, V6T 1Z1, BC, Canada
⁷ Institute for Astronomy, University of Hawaii, Honolulu, HI, 96822, USA
⁸ Canada-France-Hawaii Telescope, Kamuela, HI, 96743, USA
⁹ INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) Milano, via Bassini 15, 20133 Milano, Italy

Received: 2 September 2015
Accepted: 27 March 2016

Abstract

We investigate the evolution of the galaxy stellar mass function and stellar mass density from redshift z = 0.2 to z = 1.5 of a K_s < 22-selected sample with highly reliable photometric redshifts and over an unprecedentedly large area. Our study is based on near-infrared observations carried out with the WIRCam instrument at CFHT over the footprint of the VIPERS spectroscopic survey and benefits from the high-quality optical photometry from the CFHTLS and ultraviolet observations with the GALEX satellite. The accuracy of our photometric redshifts is σ_{Δz/ (1 + z)} < 0.03 and 0.05 for the bright (i_AB< 22.5) and faint (i_AB > 22.5) samples, respectively. The galaxy stellar mass function is measured with ~760 000 galaxies down to K_s ~ 22 and over an effective area of ~22.4 deg², the latter of which drastically reduces the statistical uncertainties (i.e. Poissonian error and cosmic variance). We point out the importance of carefully controlling the photometric calibration, whose effect becomes quickly dominant when statistical uncertainties are reduced, which will be a major issue for future cosmological surveys with EUCLID or LSST, for instance. By exploring the rest-frame (NUV−r) vs. (r−K_s) colour-colour diagram with which we separated star-forming and quiescent galaxies, (1) we find that the density of very massive log (M_∗/M_⊙) > 11.5 galaxies is largely dominated by quiescent galaxies and increases by a factor 2 from z ~ 1 to z ~ 0.2, which allows for additional mass assembly through dry mergers. (2) We also confirm the scenario in which star formation activity is impeded above a stellar mass log(ℳ^*_SF/M_⊙) = 10.64±0.01. This value is found to be very stable at 0.2 <z< 1.5. (3) We discuss the existence of a main quenching channel that is followed by massive star-forming galaxies, and we finally (4) characterise another quenching mechanism that is required to explain the clear excess of low-mass quiescent galaxies that is observed at low redshift.