C. Scarlata et al. 2007 ApJS 172 494 doi:10.1086/517972
C. Scarlata1, C. M. Carollo1, S. J. Lilly1, R. Feldmann1, P. Kampczyk1, A. Renzini2, A. Cimatti3, C. Halliday3, E. Daddi4, M. T. Sargent1, A. Koekemoer5, N. Scoville6, J.-P. Kneib7, A. Leauthaud7, R. Massey6, J. Rhodes6,8, L. Tasca7, P. Capak6, H. J. McCracken9, B. Mobasher5, Y. Taniguchi10, D. Thompson6,11, M. Ajiki12, H. Aussel13,14, T. Murayama12, D. B. Sanders13, S. Sasaki12,15, Y. Shioya15 and M. Takahashi12,15
Show affiliationsWe study the evolution since z ~ 1 of the rest-frame B luminosity function of ETGs in ~0.7 deg2 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: (1) a morphological selection based on the Zurich Estimator of Structural Types and (2) a photometric selection based on the galaxy properties in the (U - V)-MV color-magnitude diagram. We furthermore constrain both samples so as to ensure that the selected progenitors of ETGs are compatible with evolving into systems that obey the μB-rhl 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 subsamples 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 photometric and morphological samples, a deficit of up to about 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.
galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: formation; galaxies: structure
Issue 1 (2007 September)
Received 2006 June 16, accepted for publication 2007 January 26
C. Scarlata et al. 2007 ApJS 172 494
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