Bibcode
López-Sanjuan, C.; Balcells, M.; Pérez-González, Pablo G.; Barro, Guillermo; García-Dabó, C. E.; Gallego, Jesús; Zamorano, Jaime
Referencia bibliográfica
The Astrophysical Journal, Volume 710, Issue 2, pp. 1170-1178 (2010).
Fecha de publicación:
2
2010
Revista
Número de citas
39
Número de citas referidas
36
Descripción
We study the evolution of galaxy structure since z ~ 1 to the present.
From a Great Observatories Origins Deep Survey South (GOODS-S)
multi-band catalog, we define (blue) luminosity- and mass-weighted
samples, limited by MB <= -20 and M sstarf
>= 1010 M sun, comprising 1122 and 987
galaxies, respectively. We extract early-type (ET; E/S0/Sa) and
late-type (LT; Sb-Irr) subsamples by their position in the
concentration-asymmetry plane, in which galaxies exhibit a clear
bimodality. We find that the ET fraction, f ET, rises with
cosmic time, with a corresponding decrease in the LT fraction, f
LT, in both luminosity- and mass-selected samples. However,
the evolution of the comoving number density is very different: the
decrease in the total number density of MB <= -20 galaxies
since z = 1 is due to the decrease in the LT population, which accounts
for ~75% of the total star formation rate in the range under study,
while the increase in the total number density of M sstarf
>= 1010 M sun galaxies in the same redshift
range is due to the evolution of ETs. This suggests that we need a
structural transformation between LT galaxies that form stars actively
and ET galaxies in which the stellar mass is located. Comparing the
observed evolution with the gas-rich major merger rate in GOODS-S, we
infer that only ~20% of the new ET galaxies with M sstarf
>= 1010 M sun appeared since z ~ 1 can be
explained by this kind of mergers, suggesting that minor mergers and
secular processes may be the driving mechanisms of the structural
evolution of intermediate-mass (M sstarf ~ 4 ×
1010 M sun) galaxies since z ~ 1.
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