zCOSMOS - 10k-bright spectroscopic sample. The bimodality in the Galaxy Stellar Mass Function: exploring its evolution with redshift
Creators: name: Pozzetti, L.
name: Bolzonella, M.
name: Zucca, E.
name: Zamorani, G.
name: Lilly, S.
name: Renzini, A.
name: Moresco, M.
name: Mignoli, M.
name: Cassata, P.
name: Tasca, L.
name: Lamareille, F.
name: Maier, C.
name: Meneux, B.
name: Halliday, C.
name: Oesch, P.
name: Vergani, D.
name: Caputi, K.
name: Kovac, K.
name: Cimatti, A.
name: Cucciati, O.
name: Iovino, A.
name: Peng, Y.
name: Carollo, M.
name: Contini, T.
name: Kneib, J. P.
name: F'evre, O. Le
name: Mainieri, V.
name: Scodeggio, M.
name: Bardelli, S.
name: Bongiorno, A.
name: Coppa, G.
name: de la Torre, S.
name: de Ravel, L.
name: Franzetti, P.
name: Garilli, B.
name: Kampczyk, P.
name: Knobel, C.
name: Borgne, J. F. Le
name: Brun, V. Le
name: Pell`o, R.
name: Montero, E. Perez
name: Ricciardelli, E.
name: Silverman, J. D.
name: Tanaka, M.
name: Tresse, L.
name: Abbas, U.
name: Bottini, D.
name: Cappi, A.
name: Guzzo, L.
name: Koekemoer, A. M.
name: Leauthaud, A.
name: Maccagni, D.
name: Marinoni, C.
name: McCracken, H. J.
name: Memeo, P.
name: Porciani, C.
name: Scaramella, R.
name: Scarlata, C.
name: Scoville, N.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the Galaxy Stellar Mass Function (MF) up to z~1 from the zCOSMOS-bright 10k spectroscopic sample. We investigate the total MF and the contribution of ETGs and LTGs, defined by different criteria (SED, morphology or star formation). We unveil a galaxy bimodality in the global MF, better represented by 2 Schechter functions dominated by ETGs and LTGs, respectively. For the global population we confirm that low-mass galaxies number density increases later and faster than for massive galaxies. We find that the MF evolution at intermediate-low values of Mstar (logM&lt;10.6) is mostly explained by the growth in stellar mass driven by smoothly decreasing star formation activities. The low residual evolution is consistent with ~0.16 merger per galaxy per Gyr (of which fewer than 0.1 are major). We find that ETGs increase in number density with cosmic time faster for decreasing Mstar, with a median "building redshift" increasing with mass, in contrast with hierarchical models. For LTGs we find that the number density of blue or spiral galaxies remains almost constant from z~1. Instead, the most extreme population of active star forming galaxies is rapidly decreasing in number density. We suggest a transformation from blue active spirals of intermediate mass into blue quiescent and successively (1-2 Gyr after) into red passive types. The complete morphological transformation into red spheroidals, required longer time-scales or follows after 1-2 Gyr. A continuous replacement of blue galaxies is expected by low-mass active spirals growing in stellar mass. We estimate that on average ~25% of blue galaxies is transforming into red per Gyr for logM&lt;11. We conclude that the build-up of galaxies and ETGs follows the same downsizing trend with mass as the formation of their stars, converse to the trend predicted by current SAMs. We expect a negligible evolution of the global Galaxy Baryonic MF.
description: Revised version, accepted for publication on Astronomy and Astrophysics