Examinando por Autor "Ceverino, D."

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A Duality in the Origin of Bulges and Spheroidal Galaxies
(IOP Science Publishing, 2021-06-02) Constantin, L.; Pérez González, P. G.; Méndez Abreu, J.; Huertas Company, M.; Dimauro, P.; Alcalde Pampliega, B.; Buitrago, F.; Ceverino, D.; Daddi, E.; Domínguez Sánchez, H.; Espino Briones, N.; Hernán Caballero, A.; Koekemoer, A. M.; Rodighiero, G.; Constantin, L. [0000-0001-6820-0015]; Pérez González, P. G. [0000-0003-4528-5639]; Méndez Abreu, J. [0000-0002-8766-2597]; Huertas Company, M. [0000-0002-1416-8483]; Dimauro, P. [0000-0001-7399-2854]; Alcalde Pampliega, B. [0000-0002-4140-0428]; Buitrago, F. [0000-0002-2861-9812]; Caverino, D. [0000-0002-8680-248X]; Daddi, E. [0000-0002-3331-9590]; Domínguez Sánchez, H. [0000-0002-9013-1316]; Espino Briones, N. [0000-0001-6426-3844]; Hernán Caballero, A. [0000-0002-4237-5500]; Koekemoer, A. M. [0000-0002-6610-2048]; Rodighiero, G. [0000-0002-9415-2296]
Studying the resolved stellar populations of the different structural components that build massive galaxies directly unveils their assembly history. We aim at characterizing the stellar population properties of a representative sample of bulges and pure spheroids in massive galaxies (M⋆ > 1010 M⊙) in the GOODS-N field. We take advantage of the spectral and spatial information provided by SHARDS and Hubble Space Telescope data to perform the multi-image spectrophotometric decoupling of the galaxy light. We derive the spectral energy distribution separately for bulges and disks in the redshift range 0.14 < z ≤ 1 with spectral resolution R ∼ 50. Analyzing these spectral energy distributions, we find evidence of a bimodal distribution of bulge formation redshifts. We find that 33% of them present old mass-weighted ages, implying a median formation redshift ${z}_{\mathrm{form}}={6.2}_{-1.7}^{+1.5}$. They are relics of the early universe embedded in disk galaxies. A second wave, dominant in number, accounts for bulges formed at median redshift ${z}_{\mathrm{form}}={1.3}_{-0.6}^{+0.6}$. The oldest (first-wave) bulges are more compact than the youngest. Virtually all pure spheroids (i.e., those without any disk) are coetaneous with the second-wave bulges, presenting a median redshift of formation ${z}_{\mathrm{form}}={1.1}_{-0.3}^{+0.3}$. The two waves of bulge formation are distinguishable not only in terms of stellar ages but also in star formation mode. All first-wave bulges formed fast at z ∼ 6, with typical timescales around 200 Myr. A significant fraction of the second-wave bulges assembled more slowly, with star formation timescales as long as 1 Gyr. The results of this work suggest that the centers of massive disk-like galaxies actually harbor the oldest spheroids formed in the universe.