Examinando por Autor "Masegosa, J."

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Acceso Abierto
Stellar populations of galaxies in the ALHAMBRA survey up to z ∼ 1 IV. Properties of quiescent galaxies on the stellar mass–size plane
(EDP Sciences, 2019-11-13) Cenarro, A. J.; López Sanjuan, C.; Peralta de Arriba, L.; Ferreras, I.; Cerviño, M.; Márquez, I.; Masegosa, J.; Del Olmo, A.; Perea, J.; Díaz García, Pedro; Gobierno de Aragón; Ministry of Science and Technology of Taiwan (MOST); Academia Sinica; Ministerio de Ciencia e Innovación (MICINN); Generalitat Valenciana; Junta de Andalucía; Generalitat de Catalunya; Ministerio de Economía y Competitividad (MINECO); Cerviño, M. [0000-0001-8009-231X]; De Arribas, L. P. [0000-0002-3084-084X]; López Sanjuan, C. [0000-0002-5743-3160]; Márquez Pérez, I. [0000-0003-2629-1945]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Aims. We perform a comprehensive study of the stellar population properties (formation epoch, age, metallicity, and extinction) of quiescent galaxies as a function of size and stellar mass to constrain the physical mechanism governing the stellar mass assembly and the likely evolutive scenarios that explain their growth in size. Methods. After selecting all the quiescent galaxies from the ALHAMBRA survey by the dust-corrected stellar mass–colour diagram, we built a shared sample of ∼850 quiescent galaxies with reliable measurements of sizes from the HST. This sample is complete in stellar mass and luminosity, I ≤ 23. The stellar population properties were retrieved using the fitting code for spectral energy distributions called MUlti-Filter FITting for stellar population diagnostics (MUFFIT) with various sets of composite stellar population models. Age, formation epoch, metallicity, and extinction were studied on the stellar mass–size plane as function of size through a Monte Carlo approach. This accounted for uncertainties and degeneracy effects amongst stellar population properties. Results. The stellar population properties of quiescent galaxies and their stellar mass and size since z ∼ 1 are correlated. At fixed stellar mass, the more compact the quiescent galaxy, the older and richer in metals it is (1 Gyr and 0.1 dex, respectively). In addition, more compact galaxies may present slight lower extinctions than their more extended counterparts at the same stellar mass (< 0.1 mag). By means of studying constant regions of stellar population properties across the stellar mass–size plane, we obtained empirical relations to constrain the physical mechanism that governs the stellar mass assembly of the form M⋆ ∝ rcα, where α amounts to 0.50–0.55 ± 0.09. There are indications that support the idea that the velocity dispersion is tightly correlated with the stellar content of galaxies. The mechanisms driving the evolution of stellar populations can therefore be partly linked to the dynamical properties of galaxies, along with their gravitational potential.
Acceso Abierto
Torus model properties of an ultra-hard X-ray selected sample of Seyfert galaxies
(Oxford Academics: Oxford University Press, 2019-04-10) García Bernete, I.; Ramos Almeida, C.; Alonso Herrero, A.; Ward, M. J.; Acosta Pulido, J. A.; Pereira Santaella, M.; Hernán Caballero, A.; Asensio Ramos, A.; González Martín, O.; Levenson, N. A.; Mateos, S.; Carrera, F. J.; Ricci, C.; Roche, P. F.; Márquez, I.; Packham, C.; Masegosa, J.; Fuller, L.; Agencia Estatal de Investigación (AEI); Science and Technology Facilities Council (STFC); Ministerio de Economía y Competitividad (MINECO); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We characterize for the first time the torus properties of an ultra-hard X-ray (14–195 keV) volume-limited (DL < 40 Mpc) sample of 24 Seyfert (Sy) galaxies (BCS40 sample). The sample was selected from the Swift/BAT nine-month catalogue. We use high angular resolution nuclear infrared (IR) photometry and N-band spectroscopy, the CLUMPY torus models and a Bayesian tool to characterize the properties of the nuclear dust. In the case of the Sy1s, we estimate the accretion disc contribution to the subarcsecond resolution nuclear IR SEDs (∼0.4 arcsec) which is, on average, 46 ± 28, 23 ± 13, and 11 ± 5 per cent in the J, H, and K bands, respectively. This indicates that the accretion disc templates that assume a steep fall for longer wavelengths than 1 μm might underestimate its contribution to the near-IR emission. Using both optical (broad versus narrow lines) and X-ray (unabsorbed versus absorbed) classifications, we compare the global posterior distribution of the torus model parameters. We confirm that Sy2s have larger values of the torus covering factor (CT ∼ 0.95) than Sy1s (CT ∼ 0.65) in our volume-limited Seyfert sample. These findings are independent of whether we use an optical or X-ray classification. We find that the torus covering factor remains essentially constant within the errors in our luminosity range and there is no clear dependence with the Eddington ratio. Finally, we find tentative evidence that even an ultra-hard X-ray selection is missing a significant fraction of highly absorbed type 2 sources with very high covering factor tori.