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Pré-Publication, Document De Travail Année : 2007

The redshift evolution of early-type galaxies in COSMOS: Do massive early-type galaxies form by dry mergers?

C. Scarlata
  • Fonction : Auteur
C. M. Carollo
  • Fonction : Auteur
S. J. Lilly
  • Fonction : Auteur
R. Feldmann
  • Fonction : Auteur
P. Kampczyk
  • Fonction : Auteur
A. Renzini
  • Fonction : Auteur
Alessandro Cimatti
  • Fonction : Auteur
C. Halliday
  • Fonction : Auteur
Emanuele Daddi
  • Fonction : Auteur
  • PersonId : 837613
M. T. Sargent
A. Koekemoer
N. Scoville
  • Fonction : Auteur
R. Massey
  • Fonction : Auteur
J. Rhodes
B. Mobasher
  • Fonction : Auteur
Y. Taniguchi
  • Fonction : Auteur
D. Thompson
  • Fonction : Auteur
M. Ajiki
  • Fonction : Auteur
H. Aussel
T. Murayama
  • Fonction : Auteur
D. B. Sanders
  • Fonction : Auteur
Y. Shioya
  • Fonction : Auteur
M. Takahashi

Résumé

ABRIDGED: We study the evolution since z~1 of the rest-frame B luminosity function of the early-type galaxies (ETGs) in ~0.7 deg^2 in the COSMOS field. In order to identify ALL progenitors of local ETGs we construct the sample of high-z galaxies using two complementary criteria: (i) A morphological selection based on the Zurich Estimator of Structural Types, and (ii) A photometric selection based on the galaxy properties in the (U-V)-M_V color-magnitude diagram. We furthermore constrain both samples so as to ensure that the selected progenitors of ETGs are compatible with evolving into systems which obey the mu_B-r_{hl} Kormendy relation. Assuming the luminosity evolution derived from studies of the fundamental plane for high-z ETGs, our analysis shows no evidence for a decrease in the number density of the most massive ETGs out to z~ 0.7: Both the morphologically- and the photometrically-selected sub-samples show no evolution in the number density of bright (~L>2.5L*) ETGs. Allowing for different star formation histories, and cosmic variance, we estimate a maximum decrease in the number density of massive galaxies at that redshift of ~30%. We observe, however, in both the photometrical and morphological samples, a deficit of up to ~2-3 of fainter ETGs over the same cosmic period. Our results argue against a significant contribution of recent dissipationless ``dry'' mergers to the formation of the most massive ETGs. We suggest that the mass growth in low luminosity ETGs can be explained with a conversion from z~0.7 to z=0 of blue, irregular and disk galaxies into low- and intermediate-mass ``red'' ETGs, possibly also through gas rich mergers.

Dates et versions

hal-00131452 , version 1 (16-02-2007)

Identifiants

Citer

C. Scarlata, C. M. Carollo, S. J. Lilly, R. Feldmann, P. Kampczyk, et al.. The redshift evolution of early-type galaxies in COSMOS: Do massive early-type galaxies form by dry mergers?. 2007. ⟨hal-00131452⟩
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