Proyecto de Investigación: CARTOGRAFIANDO EL CIELO: SONDEOS EN EL OPTICO E INFRARROJO DE LA VIA LACTEA
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AYA2013-40611-P
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Deriving stellar parameters from GALANTE photometry: bias and precision
(Oxford Academics: Oxford University Press, 2020-04-09) Lorenzo Gutiérrez, A.; Alfaro, E. J.; Maíz Apellániz, J.; Barbá, R. H.; Marín Franch, A.; Ederoclite, A.; Cristóbal Hornillos, D.; Varela, J.; Vázquez Ramió, H.; Cenarro, A. J.; Lennon, D. J.; García Lario, P.; Daflon, S.; Borges Fernandes, M.; Agencia Estatal de Investigación (AEI); Maíz Apellániz, J. [0000-0003-0825-3443]; Marín Franch, A. [0000-0002-9026-3933]; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
In this paper, we analyse how to extract the physical properties from the GALANTE photometry of a stellar sample. We propose a direct comparison between the observational colours (photometric bands normalized to the 515 nm central wavelength) and the synthetic colours derived from different stellar libraries. We use the reduced χ2 as the figure of merit for selecting the best fitting between both colour sets. The synthetic colours of the Next Generation Spectral Library (NGSL) provide a valuable sample for testing the uncertainty and precision of the stellar parameters derived from observational data. Reddening, as an extrinsic stellar physical parameter becomes a crucial variable for accounting for the errors and bias in the derived estimates: the higher the reddenings, the larger the errors and uncertainties in the derived parameters. NGSL colours also enable us to compare different theoretical stellar libraries for the same set of physical parameters, where we see how different catalogues of models can provide very different solutions in a, sometimes, non-linear way. This peculiar behaviour makes us to be cautious with the derived physical parameters obtained from GALANTE photometry without previous detailed knowledge of the theoretical libraries used to this end. In addition, we carry out the experiment of deriving physical stellar parameters from some theoretical libraries, using some other libraries as observational data. In particular, we use the Kurucz and Coelho libraries, as input observational data, to derive stellar parameters from Coelho + TLUSTY and Kurucz + TLUSTY stellar libraries, respectively, for different photometric errors and colour excesses.© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
J-PLUS: The Javalambre Photometric Local Universe Survey
(EDP Sciences, 2019-02-21) Cenarro, A. J.; Moles, M.; Cristóbal Hornillos, D.; Marín Franch, A.; Ederoclite, A.; Varela, J.; López Sanjuan, C.; Hernández Monteagudo, C.; Angulo, R. E.; Vázquez Ramió, H.; Viironen, K.; Reis, R. R. R.; Molino, A.; Roig, F.; Vilella-Rojo, G.; Sako, M.; Sánchez Blázquez, P.; Gurung López, S.; Santos, W. A.; Telles, E.; Allende Prieto, C.; Bonatto, C.; Vilchez, J. M.; San Roman, I.; Daflon, S.; Dupke, R. A.; Greisel, N.; Jiménez Teja, Y.; Placco, V. M.; Logroño García, R.; Spinoso, D.; Maícas, N.; Izquierdo Villalba, D.; Abril, J.; Aguerri, J. A. L.; Carvano, J. M.; Bielsa de Toledo, S.; Chies Santos, A. L.; Falcón Barroso, J.; Civera, T.; Gonçalves, D. R.; Hernández Fuertes, J.; Iglesias Marzoa, R.; Whitten, D. D.; Antón, J. L.; Kruuse, K.; Lamadrid, J. L.; Bello, R.; Castillo Ramírez, J.; López Sainz, A.; Moreno Signes, A.; Chueca, S.; Díaz Martín, M. C.; Beers, T. C.; Domínguez Martínez, M.; Rueda Teruel, F.; Garzarán Calderaro, J.; Iñiguez, C.; Tilve, V.; Jiménez Ruiz, J. M.; Lasso Cabrera, N.; Alcaniz, J. S.; López Alegre, G.; Muniesa, D. J.; Lopes de Oliveira, R.; Tamm, A.; Rodríguez Llano, S.; Rueda Teruel, S.; Akras, S.; Alfaro, E. J.; Soriano Laguía, I.; Valdivielso, L.; Beasley, M. A.; Borges Fernandes, M.; Yanes Díaz, A.; Mendes de Oliveira, Claudia L.; Lyman, J. D.; Sodré, L.; Carrasco, J. M.; Coelho, P. R. T.; Xavier, H. S.; Costa Duarte, M. V.; Abramo, L. R.; Álvarez Candal, A.; Galarza, A.; Ascaso, B.; Bruzual, G.; González Serrano, J. I.; Gutiérrez Soto, L. A.; Buzzo, M. L.; Cepa, J.; Kuncarayakti, H.; Landim, R. C. G.; Cortesi, A.; De Prá, M.; Lima Neto, G. B.; Maíz Apellániz, J.; Favole, G.; Galbany, L.; Orsi, Álvaro A.; García, K.; Nogueira Cavalcante, J. P.; González Delgado, R. M.; Hernández Jiménez, J. A.; Oteo, I.; Kanaan, A.; Laur, J.; Rebassa-Mansergas, A.; Lincandro, J.; Miralda Escudé, J.; Salvador Rusiñol, N.; Sampedro, L.; Morate, D.; Novais, P. M.; Schmidtobreick, L.; Siffert, B. B.; Oncins, M.; Overzier, R. A.; Bonoli, S.; Hurier, G.; Pereira, C. B.; Díaz García, Pedro; Solano, Enrique; Gobierno de Aragón; European Commission (EC); Conselho Nacional de Desenvolvimento Científico e Tecnológico; Financiadora de Estudos e Projetos (FINEP); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); National Science Foundation (NSF); Ministerio de Economía y Competitividad (MINECO); 0000-0002-2573-2342; Jailson Souza de Alcaniz. [https://orcid.org/0000-0003-2441-1413]; Coelho, P. R. T. [0000-0003-1846-4826]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Javalambre Photometric Local Universe Survey (J-PLUS ) is an ongoing 12-band photometric optical survey, observing thousands of square degrees of the Northern Hemisphere from the dedicated JAST/T80 telescope at the Observatorio Astrofísico de Javalambre (OAJ). The T80Cam is a camera with a field of view of 2 deg2 mounted on a telescope with a diameter of 83 cm, and is equipped with a unique system of filters spanning the entire optical range (3500–10 000 Å). This filter system is a combination of broad-, medium-, and narrow-band filters, optimally designed to extract the rest-frame spectral features (the 3700–4000 Å Balmer break region, Hδ, Ca H+K, the G band, and the Mg b and Ca triplets) that are key to characterizing stellar types and delivering a low-resolution photospectrum for each pixel of the observed sky. With a typical depth of AB ∼21.25 mag per band, this filter set thus allows for an unbiased and accurate characterization of the stellar population in our Galaxy, it provides an unprecedented 2D photospectral information for all resolved galaxies in the local Universe, as well as accurate photo-z estimates (at the δ z/(1 + z)∼0.005–0.03 precision level) for moderately bright (up to r ∼ 20 mag) extragalactic sources. While some narrow-band filters are designed for the study of particular emission features ([O II]/λ3727, Hα/λ6563) up to z < 0.017, they also provide well-defined windows for the analysis of other emission lines at higher redshifts. As a result, J-PLUS has the potential to contribute to a wide range of fields in Astrophysics, both in the nearby Universe (Milky Way structure, globular clusters, 2D IFU-like studies, stellar populations of nearby and moderate-redshift galaxies, clusters of galaxies) and at high redshifts (emission-line galaxies at z ≈ 0.77, 2.2, and 4.4, quasi-stellar objects, etc.). With this paper, we release the first ∼1000 deg2 of J-PLUS data, containing about 4.3 million stars and 3.0 million galaxies at r < 21 mag. With a goal of 8500 deg2 for the total J-PLUS footprint, these numbers are expected to rise to about 35 million stars and 24 million galaxies by the end of the survey.
Hierarchical Bayesian approach for estimating physical properties in nearby galaxies: Age Maps (Paper II)
(Oxford Academics: Oxford University Press, 2019-02-15) Sánchez Gil, M. C.; Alfaro, Emilio J.; Cerviño, M.; Pérez, E.; Bland Hawthorn, J.; Death Jones, D.; Ministerio de Economía y Competitividad (MINECO); Junta de Andalucia; Agencia Estatal de Investigación (AEI); 0000-0002-2234-7035; 0000-0001-8009-231X; 0000-0001-9737-4559; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
One of the fundamental goals of modern astrophysics is to estimate the physical parameters of galaxies. We present a hierarchical Bayesian model to compute age maps from images in the H α line (taken with Taurus tunable filter, TTF), ultraviolet band (GALEX far UV, FUV), and infrared bands (Spitzer 24, 70, and 160 μm). We present the burst ages for young stellar populations in a sample of nearby and nearly face-on galaxies. The H α to FUV flux ratio is a good relative indicator of the very recent star formation history (SFH). As a nascent star-forming region evolves, the H α line emission declines earlier than the UV continuum, leading to a decrease in the H α/FUV ratio. Using star-forming galaxy models, sampled with a probabilistic formalism, and allowing for a variable fraction of ionizing photons in the clusters, we obtain the corresponding theoretical ratio H α/FUV to compare with our observed flux ratios, and thus to estimate the ages of the observed regions. We take into account the mean uncertainties and the interrelationships between parameters when computing H α/FUV. We propose a Bayesian hierarchical model where a joint probability distribution is defined to determine the parameters (age, metallicity, IMF) from the observed data (the observed flux ratios H α/FUV). The joint distribution of the parameters is described through independent and identically distributed (i.i.d.) random variables generated through MCMC (Markov Chain Monte Carlo) techniques.
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.
