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The zCOSMOS redshift survey: the three-dimensional classification cube and bimodality in galaxy physical properties

Mignoli, M. and Zamorani, G. and Scodeggio, M. and Cimatti, A. and Halliday, C. and Lilly, S. J. and Pozzetti, L. and Vergani, D. and Carollo, C. M. and Contini, T. and Le Févre, O. and Mainieri, V. and Renzini, A. and Bardelli, S. and Bolzonella, M. and Bongiorno, A. and Caputi, K. and Coppa, G. and Cucciati, O. and de la Torre, S. and de Ravel, L. and Franzetti, P. and Garilli, B. and Iovino, A. and Kampczyk, P. and Kneib, J. -P. and Knobel, C. and Kovač, K. and Lamareille, F. and Le Borgne, J. -F. and Le Brun, V. and Maier, C. and Pellò, R. and Peng, Y. and Perez Montero, E. and Ricciardelli, E. and Scarlata, C. and Silverman, J. D. and Tanaka, M. and Tasca, L. and Tresse, L. and Zucca, E. and Abbas, U. and Bottini, D. and Capak, P. and Cappi, A. and Cassata, P. and Fumana, M. and Guzzo, L. and Leauthaud, A. and Maccagni, D. and Marinoni, C. and McCracken, H. J. and Memeo, P. and Meneux, B. and Oesch, P. and Porciani, C. and Scaramella, R. and Scoville, N. (2009) The zCOSMOS redshift survey: the three-dimensional classification cube and bimodality in galaxy physical properties. Astronomy and Astrophysics, 493 (1). pp. 39-49. ISSN 0004-6361.

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Aims. We investigate the relationships between three main optical galaxy observables (spectral properties, colors, and morphology), exploiting the data set provided by the COSMOS/zCOSMOS survey. The purpose of this paper is to define a simple galaxy classification cube, with a carefully selected sample of ≈1000 galaxies. Methods. Using medium resolution spectra of the first 1k zCOSMOS-bright sample, optical photometry from the Subaru/COSMOS observations, and morphological measurements derived from ACS imaging, we analyze the properties of the galaxy population out to z~1. Applying three straightforward classification schemes (spectral, photometric, and morphological), we identify two main galaxy types, which appear to be linked to the bimodality of galaxy population. The three parametric classifications constitute the axes of a "classification cube". Results. A very good agreement exists between the classification from spectral data (quiescent/star-forming galaxies) and the one based on colors (red/blue galaxies). The third parameter (morphology) is not as well correlated with the first two; in fact, a good correlation between the spectral classification and the classification based on morphological analysis (early-/late-type galaxies) is achieved only after partially complementing the morphological classification with additional color information. Finally, analyzing the 3D-distribution of all galaxies in the sample, we find that about 85% of the galaxies show a fully concordant classification, being either quiescent, red, bulge-dominated galaxies (~20%) or star-forming, blue, disk-dominated galaxies (~65%). These results imply that the galaxy bimodality is a consistent behavior both in morphology, color, and dominant stellar population, at least out to z~1.

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Additional Information:© ESO 2008 Received 4 July 2008 Accepted 6 October 2008 Based on observations undertaken at the European Southern Observatory (ESO) Very Large Telescope (VLT) under Large Program 175.A-0839. Also based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, operated by AURA Inc., under NASA contract NAS 5-26555, with the Subaru Telescope, operated by the National Astronomical Observatory of Japan, with the telescopes of the National Optical Astronomy Observatory, operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation, and with the Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii. Acknowledgements. This work was partially supported by INAF under PRIN-2006/ and by ASI under grant ASI/COFIS I/016/07/0.
Funding AgencyGrant Number
NASANAS 5-26555
Istituto Nazionale di Astrofisica (Italy)PRIN-2006/
Agenzia Spaziale Italiana (Italy)ASI/COFIS I/016/07/0
European Southern Observatory Very Large TelescopeLarge Program 175.A-0839
National Astronomical Observatory of JapanUNSPECIFIED
Association of Universities for Research in Astronomy, Inc.UNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Centre National de la Recherche Scientifique de FranceUNSPECIFIED
University of HawaiiUNSPECIFIED
Subject Keywords:galaxies-general;galaxies-evolution;galaxies-fundamental parameters
Record Number:CaltechAUTHORS:MIGaanda09
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Official Citation: The zCOSMOS redshift survey: the three-dimensional classification cube and bimodality in galaxy physical properties M. Mignoli, G. Zamorani, M. Scodeggio, A. Cimatti, C. Halliday, S. J. Lilly, L. Pozzetti, D. Vergani, C. M. Carollo, T. Contini, O. Le Févre, V. Mainieri, A. Renzini, S. Bardelli, M. Bolzonella, A. Bongiorno, K. Caputi, G. Coppa, O. Cucciati, S. de la Torre, L. de Ravel, P. Franzetti, B. Garilli, A. Iovino, P. Kampczyk, J.-P. Kneib, C. Knobel, K. Kova, F. Lamareille, J.-F. Le Borgne, V. Le Brun, C. Maier, R. Pellò, Y. Peng, E. Perez Montero, E. Ricciardelli, C. Scarlata, J. D. Silverman, M. Tanaka, L. Tasca, L. Tresse, E. Zucca, U. Abbas, D. Bottini, P. Capak, A. Cappi, P. Cassata, M. Fumana, L. Guzzo, A. Leauthaud, D. Maccagni, C. Marinoni, H. J. McCracken, P. Memeo, B. Meneux, P. Oesch, C. Porciani, R. Scaramella and N. Scoville A&A 493 (1) 39-49 (2009) DOI: 10.1051/0004-6361:200810520
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13651
Deposited By: Arun Sannuti
Deposited On:24 Jun 2009 22:04
Last Modified:06 Jul 2015 20:52

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