Person: Alcalde Pampliega, Belén
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First Name
Belén
Last Name
Alcalde Pampliega
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Física de la Tierra
Identifiers
7 results
Search Results
Now showing 1 - 7 of 7
Item A duality in the origin of bulges and spheroidal galaxies(Astrophysical journal, 2021) Costantin, Luca; Pérez González, Pablo Guillermo; Méndez Abreu, Jairo; Huertas Company, Marc; Dimauro, Paola; Alcalde Pampliega, Belén; Buitrago, Fernando; Ceverino, Daniel; Daddi, Emanuele; Domínguez Sánchez, Helena; Espino Briones, Néstor; Hernán Caballero, Antonio; Koekemoer, Anton M.; Rodighiero, GiuliaStudying the resolved stellar populations of the different structural components which 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* > 10^(10) Mסּ ) in the GOODS-N field. We take advantage of the spectral and spatial information provided by SHARDS and HST data to perform the multi-image spectro-photometrical 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 SEDs, we find evidences 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_(form) = 6.2^(+1.5)_(−1.7). 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_(form) = 1.3^(+0.6)_(−0.6). The oldest (1st-wave) bulges are more compact than the youngest. Virtually all pure spheroids (i.e., those without any disk) are coetaneous with the 2nd-wave bulges, presenting a median redshift of formation z_(form) = 1.1^(+0.3)_(−0.3). The two waves of bulge formation are not only distinguishable in terms of stellar ages, but also in star formation mode. All 1st-wave bulges formed fast at z ∼ 6, with typical timescales around 200 Myr. A significant fraction of the 2nd-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.Item Emission line galaxies in the SHARDS Hubble frontier fields. II. Limits on Lyman-continuum escape fractions of lensed emission line galaxies at redshifts 2(Astrophysical journal, 2022) Alcalde Pampliega, BelénWe present an investigation of escape fractions of UV photons from a unique sample of lensed low-mass emission line–selected galaxies at z < 3.5 found in the SHARDS Hubble Frontier Fields medium-band survey. We have used this deep imaging survey to locate 42 relatively low-mass galaxies down to log (M_(*)/M_(ꙩ))= 7 in the redshift range 2.4Item The first massive galaxies formed in the Universe: selection and characterization of optically faint, infrared-bright galaxies in the first 2 Gyr of the Universe(2021) Alcalde Pampliega, Belén; Pérez González, Pablo G.; Barro, GuillermoThe ultimate goal in galaxy studies is having a complete picture of galaxy formation and evolution across the history of the Universe. A robust determination of the abundance of massive (an even quiescent) galaxies at high redshift is essential to constrain current models of galaxy formation and alleviate the tension between existing models and observations. In this context, this Ph.D. Thesis addresses the challenge of studying the build-up of massive galaxies adding a new population of optically faint Balmer Break Galaxies (BBGs), which are bright at longer wave lengths, to the general population of massive galaxies at z È 3...Item Lack of influence of the environment in the earliest stages of massive galaxy formation(Monthly notices of The Royal Astronomical Society, 2022) 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.Item Investigating the effect of galaxy interactions on the enhancement of active galactic nuclei at 0.5 < z < 3.0(Astrophysical journal, 2020) Alcalde Pampliega, BelénGalaxy interactions and mergers are thought to play an important role in the evolution of galaxies. Studies in the nearby universe show a higher AGN fraction in interacting and merging galaxies than their isolated counterparts, indicating that such interactions are important contributors to black hole growth. To investigate the evolution of this role at higher redshifts, we have compiled the largest known sample of major spectroscopic galaxy pairs (2381 with ∆V < 5000 km s^(−1) ) at 0.5 < z < 3.0 from observations in the COSMOS and CANDELS surveys. We identify X-ray and IR AGN among this kinematic pair sample, a visually identified sample of mergers and interactions, and a mass-, redshift- and environment-matched control sample for each in order to calculate AGN fractions and the level of AGN enhancement as a function of relative velocity, redshift, and X-ray luminosity. While we see a slight increase in AGN fraction with decreasing projected separation, overall, we find no significant enhancement relative to the control sample at any separation. In the closest projected separation bin (< 25 kpc, ∆V < 1000 km s^(−1)), we find enhancements of a factor of 0.94^(+0.21)_(−0.16) and 1.00^(+0.58)_(−0.31) for X-ray and IR-selected AGN, respectively. While we conclude that galaxy interactions do not significantly enhance AGN activity on average over 0.5 < z < 3.0 at these separations, given the errors and the small sample size at the closest projected separations, our results would be consistent with the presence of low-level AGN enhancement.Item Differences and similarities of stellar populations in LAEs and LBGs at z ∼ 3.4−6.8(Monthly notices of The Royal Astronomical Society, 2020) Arrabal Haro, P.; Rodríguez Espinosa, J.M.; Muñoz Tuñón, C.; Sobral, D.; Lumbreras Calle, A.; Boquien, M.; Hernán Caballero, A.; Rodríguez Muñoz, L.; Alcalde Pampliega, BelénLyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) represent the most common groups of star-forming galaxies at high z, and the differences between their inherent stellar populations (SPs) are a key factor in understanding early galaxy formation and evolution. We have run a set of SP burst-like models for a sample of 1558 sources at 3.4Item From Naked Spheroids to Disky Galaxies: How Do Massive Disk Galaxies Shape Their Morphology?(Astrophysical journal, 2022) 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.