The cosmic star formation rate evolution from z = 5 to z = 0 from the VIMOS VLT deep survey*
Laboratoire d'Astrophysique de Marseille (UMR 6110), CNRS-Université de Provence, BP 8, 13376 Marseille Cedex 12, France e-mail: Laurence.Tresse@oamp.fr
2 Institute for Astronomy, 2680 Woodlawn Dr., University of Hawaii, Honolulu, Hawaii 96822, USA
3 INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
4 Integral Science Data Centre, Ch. d'Écogia 16, 1290 Versoix, Switzerland
5 Geneva Observatory, Ch. de Maillettes 51, 1290 Sauverny, Switzerland
6 INAF-IASF, via Bassini 15, 20133 Milano, Italy
7 Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (UMR 5572), CNRS-Université Paul Sabatier, 14 avenue E. Belin, 31400 Toulouse, France
8 INAF-IRA, via Gobetti 101, 40129 Bologna, Italy
9 INAF-Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone, Italy
10 INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, 80131 Napoli, Italy
11 Institut d'Astrophysique de Paris (UMR 7095), 98bis boulevard Arago, 75014 Paris, France
12 School of Physics & Astronomy, University of Nottingham, University Park, Nottingham NG72RD, UK
13 Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
14 INAF-Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy
15 Observatoire de Paris-LERMA, 61 avenue de l'Observatoire, 75014 Paris, France
16 Università di Bologna, Dipartimento di Astronomia, via Ranzani 1, 40127 Bologna, Italy
17 Centre de Physique Théorique (UMR 6207), CNRS-Université de Provence, 13288 Marseille, France
Accepted: 26 April 2007
Context.The VIMOS VLT Deep Survey (VVDS) was undertaken to map the evolution of galaxies, large scale structures, and active galaxy nuclei from the redshift spectroscopic measurements of ~105 objects down to an apparent magnitude , in combination with a multi-wavelength acquisition for radio, infrared, optical, ultraviolet, and X-rays data.
Aims.We present the evolution of the comoving star formation rate (SFR) density in the redshift range using the first epoch data release of the VVDS, that is 11564 spectra over 2200 arcmin2 in two fields of view, the VVDS-0226-04 and the VVDS-CDFS-0332-27, and the cosmological parameters (, , , 0.7, 0.7).
Methods.We study the multi-wavelength non dust-corrected luminosity densities at from the rest-frame far ultraviolet to the optical passbands, and the rest-frame 1500 Å luminosity functions and densities at .
Results.They evolve from to according to with , and 0.30 in the FUV-1500, NUV-2800, U-3600, B-4400, V-5500, R-6500, and I-7900 passbands, respectively. From to the B-band density for the irregular-like galaxies decreases markedly by a factor 3.5 while it increases by a factor 1.7 for the elliptical-like galaxies. We identify several SFR periods; from to 3.4 the FUV-band density increases by at most 0.5 dex, from to 1.2 it decreases by 0.08 dex, from to it declines steadily by 0.6 dex. For the most luminous galaxies the FUV-band density drops by 2 dex from to , and for the intermediate galaxies it drops by 2 dex from to . Comparing with dust corrected surveys, at the FUV seems obscured by a constant factor of –2 mag, while at it seems progressively less obscured by up to –1 mag when the dust-deficient early-type population is increasingly dominating the B-band density.
Conclusions.The VVDS results agree with a downsizing picture where the most luminous sources cease to efficiently produce new stars 12 Gyrs ago (at ), while intermediate luminosity sources keep producing stars until 2.5 Gyrs ago (at ). A modest contribution of dry mergers and morphologies evolving towards early-type galaxies might contribute to increase the number density of the bright early types at . Our observed SFR density is not in agreement with a continuous smooth decrease since .
Key words: cosmology: observations / galaxies: evolution / galaxies: luminosity function, mass function
Based on observations collected at the European Southern Observatory Very Large Telescope, Paranal, Chile, program 070.A-9007(A), and on data obtained at the Canada-France-Hawaii Telescope, operated by the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, the National Research Council of Canada, and the University of Hawaii.
© ESO, 2007