Arnouts, S. and Walcher, C. J. and Le Fèvre, O. and Zamorani, G. and Ilbert, O. and Le Brun, V. and Pozzetti, L. and Bardelli, S. and Tresse, L. and Zucca, E. and Charlot, S. and Lamareille, F. and McCracken, H. J. and Bolzonella, M. and Iovino, A. and Lonsdale, C. and Polletta, M. and Surace, J. and Bottini, D. and Garilli, B. and Maccagni, D. and Picat, J. P. and Scaramella, R. and Scodeggio, M. and Vettolani, G. and Zanichelli, A. and Adami, C. and Cappi, A. and Ciliegi, P. and Contini, T. and de la Torre, S. and Foucaud, S. and Franzetti, P. and Gavignaud, I. and Guzzo, L. and Marano, B. and Marinoni, C. and Mazure, A. and Meneux, B. and Merighi, R. and Paltani, S. and Pellò, R. and Pollo, A. and Radovich, M. and Temporin, S. and Vergani, D. (2007) The SWIRE-VVDS-CFHTLS surveys: stellar mass assembly over the last 10 Gyr. Evidence for a major build up of the red sequence between z = 2 and z = 1. Astronomy and Astrophysics, 476 (1). pp. 137-150. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:20091014-095610915
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We present an analysis of the stellar mass growth over the last 10 Gyr (z ≤ 2) using a unique large sample of galaxies selected at 3.6 μm. We have assembled accurate photometric and spectroscopic redshifts for ~21 200 and 1500 galaxies, respectively, with F(3.6 μm) ≥ 9.0 μJy by combining data from Spitzer-SWIRE IRAC, the VIMOS VLT Deep Survey (VVDS), UKIDSS and very deep optical CFHTLS photometry. We split our sample into quiescent (red) and active (blue) galaxies on the basis of an SED fitting procedure that we have compared with the strong rest-frame color bimodality (NUV −r')_(ABS). The present sample contains ∼4400 quiescent galaxies. Our measurements of the K-rest frame luminosity function and luminosity density evolution support the idea that a large fraction of galaxies is already assembled at z ~ 1.2, with almost 80% and 50% of the active and quiescent populations already in place, respectively. Based on the analysis of the evolution of the stellar mass-to-light ratio (in K-band) for the spectroscopic sub-sample, we derive the stellar mass density for the entire sample. We find that the global evolution of the stellar mass density is well reproduced by the star formation rate derived from UV based measurements when an appropriate dust correction is applied, which supports the idea of an initial mass function that is on average universal. Over the last 8 Gyr (z ≤ 1.2) we observe that the stellar mass density of the active population shows a modest mass growth rate (ρ ~ 0.005(±0.005) M_⊙/Mpc^3/yr), consistent with a constant stellar mass density, ρ_(active) ~ 3.1 × 10^8 M_⊙/Mpc^3. In contrast, an increase by a factor of ~2 for the quiescent population over the same timescale is observed. As a consequence, the growth of the stellar mass in the quiescent population must be due to the shutoff of star formation in active galaxies that migrate into the quiescent population. We estimate this stellar mass flux to be ρ_(A→Q) ~ 0.017(±0.004) M_⊙/Mpc^3/yr, which balances the major fraction of new stars born according to our best SFR estimate (ρ = 0.025(±0.003) M_⊙/Mpc^3/yr). From z = 2 to z = 1.2, we observe a major build-up of the quiescent population with an increase by a factor of ~10 in stellar mass (a mass growth rate of ~0.063 M_⊙/Mpc^3/yr). This rapid evolution suggests that we are observing the epoch when, for the first time in the history of the universe, an increasing fraction of galaxies end their star formation activity and start to build up the red sequence.
|Additional Information:||© ESO 2007. Received 12 April 2007. Accepted 18 September 2007. We are grateful to the referee for his careful reading of the manuscript and his suggestions. S.A. wants to thank B. Milliard for useful discussions. This work has been partially supported by the CNRS-INSU and the “Progamme National de Cosmologie” (France), the “Programme National Galaxies” (France) and a grant awarded for “EFIGI project” (grant # 45500) from the French research ministry. C.J.W. is supported by the MAGPOP Marie Curie EU Research and Training Network.|
|Subject Keywords:||galaxies : luminosity function; mass function; galaxies : formation|
|Official Citation:||The SWIRE-VVDS-CFHTLS surveys: stellar mass assembly over the last 10 Gyr. Evidence for a major build up of the red sequence between z = 2 and z = 1 S. Arnouts, C. J. Walcher, O. Le Fèvre, G. Zamorani, O. Ilbert, V. Le Brun, L. Pozzetti, S. Bardelli, L. Tresse, E. Zucca, S. Charlot, F. Lamareille, H. J. McCracken, M. Bolzonella, A. Iovino, C. Lonsdale, M. Polletta, J. Surace, D. Bottini, B. Garilli, D. Maccagni, J. P. Picat, R. Scaramella, M. Scodeggio, G. Vettolani, A. Zanichelli, C. Adami, A. Cappi, P. Ciliegi, T. Contini, S. de la Torre, S. Foucaud, P. Franzetti, I. Gavignaud, L. Guzzo, B. Marano, C. Marinoni, A. Mazure, B. Meneux, R. Merighi, S. Paltani, R. Pellò, A. Pollo, M. Radovich, S. Temporin and D. Vergani A&A 476 (1) 137-150 (2007) DOI: 10.1051/0004-6361:20077632|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||26 Oct 2009 17:39|
|Last Modified:||26 Dec 2012 11:28|
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