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Título:
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The minor role of gas-rich major mergers in the rise of intermediate-mass early types at z ? 1
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Autores:
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López Sanjuan, Carlos ;
Balcells, Marc ;
Pérez González, Pablo Guillermo ;
Barro, Guillermo ;
García Dabó, César Enrique ;
Gallego Maestro, Jesús ;
Zamorano Calvo, Jaime
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Tipo de documento:
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texto impreso
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Editorial:
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American Astronomical Society, 2010-02-20
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Física: Astrofísica
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Materia = Ciencias: Física: Astronomía
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Tipo = Artículo
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Resumen:
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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 ?, 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 ? 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 ? 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 ?) galaxies since z ~ 1.
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En línea:
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https://eprints.ucm.es/33916/1/jesusgallego33libre.pdf
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