Pérez González, Pablo Guillermo

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First Name
Pablo Guillermo
Last Name
Pérez González
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Astronomía y Astrofísica
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Now showing 1 - 2 of 2
  • Publication
    Lack of influence of the environment in the earliest stages of massive galaxy formation
    (Oxford University Press., 2022-12-16) Annunziatella, Marianna; Pérez González, Pablo Guillermo; García Argumánez, Ángela; Barro, Guillermo; Alcalde Pampliega, Belén; Constantin, Luca; Koekemoer, Anton M.; Mérida, Rosa M.
    We investigate how the environment affects the assembly history of massive galaxies. For that purpose, we make use of SHARDS and HST spectro-photometric data, whose depth, spectral resolution, and wavelength coverage allow to perform a detailed analysis of the stellar emission as well as obtaining unprecedentedly accurate photometric redshifts. This expedites a sufficiently accurate estimate of the local environment and a robust derivation of the star formation histories of a complete sample of 332 massive galaxies (> 10^(10)Mꙩ) at redshift 1 ≤ z ≤ 1.5 in the GOODS-N field. We find that massive galaxies in this redshift range avoid the lowest density environments. Moreover, we observed that the oldest galaxies in our sample with with mass-weighted formation redshift z_(M−w) ≥ 2.5, avoid the highest density regions, preferring intermediate environments. Younger galaxies, including those with active star formation, tend to live in denser environments (Σ = 5.0^(24.8)_(1.1) × 10^(10)MꙩMpc^(−2)). This behavior could be expected if those massive galaxies starting their formation first would merge with neighbors and sweep their environment earlier. On the other hand, galaxies formed more recently (z_(M−w) < 2.5) are accreted into large scale structures at later times and we are observing them before sweeping their environment or, alternatively, they are less likely to affect their environment. However, given that both number and mass surface densities of neighbor galaxies is relatively low for the oldest galaxies, our results reveal a very weak correlation between environment and the first formation stages of the earliest massive galaxies.
  • Publication
    From Naked Spheroids to Disky Galaxies: How Do Massive Disk Galaxies Shape Their Morphology?
    (IOP Publishing, 2022-04-01) Costantin, Luca; Pérez González, Pablo Guillermo; Méndez Abreu, Jairo; Huertas Company, Marc; Alcalde Pampliega, Belén; Balcells, Marc; Barro, Guillermo; Ceverino, Daniel; Dimauro, Paola; Domínguez Sánchez, Helena; Espino Briones, Néstor; Koekemoer, Anton M.
    We investigate the assembly history of massive disk galaxies and describe how they shape their morphology through cosmic time. Using SHARDS and HST data, we modeled the surface brightness distribution of 91 massive galaxies at redshift 0.14 < z <= 1 in the wavelength range 0.5-1.6 mu m, deriving the uncontaminated spectral energy distributions of their bulges and disks separately. This spectrophotometric decomposition allows us to compare the stellar population properties of each component in individual galaxies. We find that the majority of massive galaxies (similar to 85%) build inside-out, growing their extended stellar disk around the central spheroid. Some bulges and disks could start forming at similar epochs, but these bulges grow more rapidly than their disks, assembling 80% of their mass in similar to 0.7 and similar to 3.5 Gyr, respectively. Moreover, we infer that both older bulges and older disks are more massive and compact than younger stellar structures. In particular, we find that bulges display a bimodal distribution of mass-weighted ages; i.e., they form in two waves. In contrast, our analysis of the disk components indicates that they form at z similar to 1 for both first- and second-wave bulges. This translates to first-wave bulges taking longer to acquire a stellar disk (5.2 Gyr) compared to second-wave, less compact spheroids (0.7 Gyr). We do not find distinct properties (e.g., mass, star formation timescale, and mass surface density) for the disks in both types of galaxies. We conclude that the bulge mass and compactness mainly regulate the timing of the stellar disk growth, driving the morphological evolution of massive disk galaxies.