The zCOSMOS redshift survey: evolution of the light in bulges and discs since z ~ 0.8

L. A. M. Tasca*, L. Tresse, O. Le Fevre, O. Ilbert, S. J. Lilly, G. Zamorani, C. Lopez-Sanjuan, L. C. Ho, S. Bardelli, A. Cattaneo, O. Cucciati, D. Farrah, A. Iovino, A. M. Koekemoer, C. T. Liu, R. Massey, A. Renzini, Y. Taniguchi, N. Welikala, E. ZuccaC. M. Carollo, T. Contini, J. -P. Kneib, V. Mainieri, M. Scodeggio, M. Bolzonella, A. Bongiorno, K. Caputi, S. de la Torre, P. Franzetti, B. Garilli, L. Guzzo, P. Kampczyk, C. Knobel, K. Kovac, F. Lamareille, J. -F. Le Borgne, V. Le Brun, C. Maier, M. Mignoli, R. Pello, Y. Peng, E. Perez Montero, R. M. Rich, M. Tanaka, D. Vergani, R. Bordoloi, A. Cappi, A. Cimatti, G. Coppa, H. J. McCracken, M. Moresco, L. Pozzetti, D. Sanders, K. Sheth

*Corresponding author for this work

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Abstract

We studied the chronology of galactic bulge and disc formation by analysing the relative contributions of these components to the B-band rest-frame luminosity density at different epochs. We present the first estimate of the evolution of the fraction of rest-frame B-band light in galactic bulges and discs since redshift z ∼ 0.8. We performed a bulge-to-disc decomposition of HST/ACS images of 3266 galaxies in the zCOSMOS-bright survey with spectroscopic redshifts in the range 0.7 ≤ z ≤ 0.9. We find that the fraction of B-band light in bulges and discs is (26 ± 4)% and (74 ± 4)%, respectively. When compared with rest-frame B-band measurements of galaxies in the local Universe in the same mass range (109 M⊙ ⪉ M ⪉ 1011.5 M_{⊙}), we find that the B-band light in discs decreases by 30% from z ∼ 0.7-0.9 to z ∼ 0, while the light from the bulge increases by 30% over the same period of time. We interpret this evolution as the consequence of star formation and mass assembly processes, as well as morphological transformation, which gradually shift stars formed at half the age of the Universe from star-forming late-type/irregular galaxies to earlier types and ultimately into spheroids. Based on observations obtained at the European Southern Observatory (ESO) Very Large Telescope (VLT), Paranal, Chile, as part of the Large Program 175.A-0839 (the zCOSMOS Spectroscopic Redshift Survey).
Original languageEnglish
Article numberL12
Number of pages5
JournalAstronomy & astrophysics
Volume564
DOIs
Publication statusPublished - Apr-2014

Keywords

  • galaxies: bulges
  • galaxies: evolution
  • galaxies: luminosity function, mass function
  • galaxies: distances and redshifts
  • galaxies: fundamental parameters
  • HUBBLE-SPACE-TELESCOPE
  • STAR-FORMATION RATE
  • VLT DEEP SURVEY
  • LUMINOSITY FUNCTIONS
  • FORMATION HISTORY
  • GALAXY FORMATION
  • ADVANCED CAMERA
  • FORMING GALAXY
  • SURVEY COSMOS
  • MASS

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