Examinando por Autor "Constantin, L."

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Acceso Abierto
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.
Restringido
Deconstructing double-barred galaxies in 2D and 3D – II. Two distinct groups of inner bars.
(Oxford Academics: Blackwell Publishing, 2020-03-20) De Lorenzo Cáceres, A.; Méndez Abreu, J.; Thorne, B.; Constantin, L.; Science and Technology Facilities Council (STFC); Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Constantin, L. [https://orcid.org/0000-0001-6820-0015]; Mendez Abreu, J. [https://orcid.org/0000-0002-8766-2597]; De Lorenzo Cáceres, A. [https://orcid.org/0000-0002-9744-3486]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The intrinsic photometric properties of inner and outer stellar bars within 17 double-barred galaxies are thoroughly studied through a photometric analysis consisting of (i) two-dimensional (2D) multicomponent photometric decompositions, and (ii) three-dimensional (3D) statistical deprojections for measuring the thickening of bars, thus retrieving their 3D shape. The results are compared with previous measurements obtained with the widely used analysis of integrated light. Large-scale bars in single- and double-barred systems show similar sizes, and inner bars may be longer than outer bars in different galaxies. We find two distinct groups of inner bars attending to their in-plane length and ellipticity, resulting in a bimodal behaviour for the inner/outer bar length ratio. Such bimodality is related neither to the properties of the host galaxy nor the dominant bulge, and it does not show a counterpart in the dimension off the disc plane. The group of long inner bars lays at the lower end of the outer bar length versus ellipticity correlation, whereas the short inner bars are out of that relation. We suggest that this behaviour could be due to either a different nature of the inner discs from which the inner bars are dynamically formed or a different assembly stage for the inner bars. This last possibility would imply that the dynamical assembly of inner bars is a slow process taking several Gyr to happen. We have also explored whether all large-scale bars are prone to develop an inner bar at some stage of their lives, possibility we cannot fully confirm or discard.