Proyecto de Investigación: EVOLUCION DE GALAXIAS
Cargando...
Colaboradores
Financiadores
ID
AYA2014-58861-C3-1-P
Autores
Publicaciones
The OTELO survey. Nature and mass-metallicity relation for Hα emitters at z ∼ 0.4
(EDP Sciences, 2020-04-24) Nadolny, J.; Lara López, M. A.; Cerviño, M.; Bongiovanni, Á.; Cepa, J.; De Diego, J. A.; Pérez García, A. M.; Pérez Martínez, R.; Sánchez Portal, M.; Alfaro, Emilio J.; Castañeda, H. O.; Gallego, J.; González, J. J.; González Serrano, J. I.; Padilla Torres, C. P.; Pintos Castro, I.; Povic, M.; Ministerio de Economía y Competitividad (MINECO); Universidad Nacional Autónoma de México (UNAM); Agencia Estatal de Investigación (AEI); 0000-0003-1634-3588; 0000-0002-9127-5522; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The OSIRIS Tunable Filter Emission Line Object (OTELO) survey is a very deep, blind exploration of a selected region of the Extended Groth Strip and is designed for finding emission-line sources (ELSs). The survey design, observations, data reduction, astrometry, and photometry, as well as the correlation with ancillary data used to obtain a final catalogue, including photo-z estimates and a preliminary selection of ELS, were described in a previous contribution.
Aims. Here, we aim to determine the main properties and luminosity function (LF) of the [O III] ELS sample of OTELO as a scientific demonstration of its capabilities, advantages, and complementarity with respect to other surveys.
Methods. The selection and analysis procedures of ELS candidates obtained using tunable filter pseudo-spectra are described. We performed simulations in the parameter space of the survey to obtain emission-line detection probabilities. Relevant characteristics of [O III] emitters and the LF ([O III]), including the main selection biases and uncertainties, are presented.
Results. From 541 preliminary emission-line source candidates selected around z & x2004;=& x2004;0.8, a total of 184 sources were confirmed as [O III] emitters. Consistent with simulations, the minimum detectable line flux and equivalent width in this ELS sample are similar to 5 x 10(-19) erg s(-1) cm(2) and similar to 6 angstrom, respectively. We are able to constrain the faint-end slope (alpha & x2004;=& x2004;-1.03 +/- 0.08) of the observed LF ([O III]) at a mean redshift of z & x2004;=& x2004;0.83. This LF reaches values that are approximately ten times lower than those from other surveys. The vast majority (84%) of the morphologically classified [O III] ELSs are disc-like sources, and 87% of this sample is comprised of galaxies with stellar masses of M-& x22c6;& x2004;< & x2004;10(10) M-circle dot.
System initial mass function of the 25 Ori group from planetary-mass objects to intermediate/high-mass stars
(Oxford Academics: Oxford University Press, 2019-04-18) Suárez, G.; Downes, J. J.; Román Zúñiga, C.; Cerviño, M.; Briceño, C.; Petr Gotzens, M. G.; Vivas, K.; Consejo Nacional de Ciencia y Tecnología (CONACYT); Universidad Nacional Autónoma de México (UNAM); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Suárez, G. [0000-0002-2011-4924]; Downes, J. J. [0000-0001-6559-2578]; Román Zúñiga, C. [0000-0001-8600-4798]; Cerviño, M. [0000-0001-8009-231X]; Briceño, C. [0000-0001-7124-4094]; Vivas, K. [0000-0003-4341-6172]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The stellar initial mass function (IMF) is an essential input for many astrophysical studies but only in a few cases has it been determined over the whole cluster mass range, limiting the conclusions about its nature. The 25 Orionis group (25 Ori) is an excellent laboratory for investigating the IMF across the entire mass range of the population, from planetary-mass objects to intermediate/high-mass stars. We combine new deep optical photometry with optical and near-infrared data from the literature to select 1687 member candidates covering a 1.1° radius area in 25 Ori. With this sample we derived the 25 Ori system IMF from 0.012 to 13.1 M⊙. This system IMF is well described by a two-segment power law with Γ = −0.74 ± 0.04 for m < 0.4 M⊙ and Γ = 1.50 ± 0.11 for m ≥ 0.4 M⊙. It is also well described over the whole mass range by a tapered power-law function with Γ = 1.10 ± 0.09, mp = 0.31 ± 0.03 and β = 2.11 ± 0.09. The best lognormal representation of the system IMF has mc = 0.31 ± 0.04 and σ = 0.46 ± 0.05 for m < 1 M⊙. This system IMF does not present significant variations with the radii. We compared the resultant system IMF as well as the brown dwarf/star ratio of 0.16 ± 0.03 that we estimated for 25 Ori with that of other stellar regions with diverse conditions and found no significant discrepancies. These results support the idea that general star-formation mechanisms are probably not strongly dependent on environmental conditions. We found that the substellar and stellar objects in 25 Ori do not have any preferential spatial distributions and confirmed that 25 Ori is a gravitationally unbound stellar association.
The OTELO survey I. Description, data reduction, and multi-wavelength catalogue
(EDP Sciences, 2019-10-14) Ramón Pérez, M.; Pérez García, A. M.; Cepa, J.; Cerviño, M.; Nadolny, J.; Pérez Martínez, R.; Alfaro, Emilio J.; Castañeda, H. O.; De Diego, J. A.; Ederoclite, A.; Fernández Lorenzo, M.; Gallego, J.; González, J. J.; González Serrano, J. I.; Lara López, M. A.; Oteo Gómez, I.; Padilla Torres, C. P.; Pintos Castro, I.; Povic, M.; Sánchez Portal, M.; Jones, H.; Bland Hawthorn, J.; Cabrera Lavers, A.; Bongiovanni, Á.; Agence Nationale de la Recherche (ANR); Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Bongiovanni, Á. [0000-0002-3557-3234]
Context. The evolution of galaxies through cosmic time is studied observationally by means of extragalactic surveys. The usefulness of these surveys is greatly improved by increasing the cosmological volume, in either depth or area, and by observing the same targets in different wavelength ranges. A multi-wavelength approach using different observational techniques can compensate for observational biases.
Aims. The OTELO survey aims to provide the deepest narrow-band survey to date in terms of minimum detectable flux and emission line equivalent width in order to detect the faintest extragalactic emission line systems. In this way, OTELO data will complements other broad-band, narrow-band, and spectroscopic surveys.
Methods. The red tunable filter of the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC) is used to scan a spectral window centred at 9175 Å, which is free from strong sky emission lines, with a sampling interval of 6 Å and a bandwidth of 12 Å in the most deeply explored EGS region. Careful data reduction using improved techniques for sky ring subtraction, accurate astrometry, photometric calibration, and source extraction enables us to compile the OTELO catalogue. This catalogue is complemented with ancillary data ranging from deep X-ray to far-infrared, including high resolution HST images, which allow us to segregate the different types of targets, derive precise photometric redshifts, and obtain the morphological classification of the extragalactic objects detected.
Results. The OTELO multi-wavelength catalogue contains 11 237 entries and is 50% complete at AB magnitude 26.38. Of these sources, 6600 have photometric redshifts with an uncertainty δ zphot better than 0.2 (1+zphot). A total of 4336 of these sources correspond to preliminary emission line candidates, which are complemented by 81 candidate stars and 483 sources that qualify as absorption line systems. The OTELO survey results will be released to the public on the second half of 2019.
Galaxy classification: Deep learning on the OTELO and COSMOS databases
(EDP Sciences, 2020-06-25) De Diego, J. A.; Nadolny, J.; Bongiovanni, Á.; Cepa, J.; Povic, M.; Pérez García, A. M.; Padilla Torres, C. P.; Lara López, M. A.; Cerviño, M.; Pérez Martínez, R.; Alfaro, Emilio J.; Castañeda, H. O.; Fernández Lorenzo, M.; Gallego, J.; González, J. J.; González Serrano, J. I.; Pintos Castro, I.; Sánchez Portal, M.; Cedrés, B.; González Otero, M.; Jones, D. Heath; Bland Hawthorn, J.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); De Diego, J. A. https://orcid.org/0000-0001-7040-069X; 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
Context. The accurate classification of hundreds of thousands of galaxies observed in modern deep surveys is imperative if we want to understand the universe and its evolution.Aims. Here, we report the use of machine learning techniques to classify early- and late-type galaxies in the OTELO and COSMOS databases using optical and infrared photometry and available shape parameters: either the Sersic index or the concentration index.Methods. We used three classification methods for the OTELO database: (1) u-r color separation, (2) linear discriminant analysis using u-r and a shape parameter classification, and (3) a deep neural network using the r magnitude, several colors, and a shape parameter. We analyzed the performance of each method by sample bootstrapping and tested the performance of our neural network architecture using COSMOS data.Results. The accuracy achieved by the deep neural network is greater than that of the other classification methods, and it can also operate with missing data. Our neural network architecture is able to classify both OTELO and COSMOS datasets regardless of small differences in the photometric bands used in each catalog.Conclusions. In this study we show that the use of deep neural networks is a robust method to mine the cataloged data.
The OTELO survey III. Demography, morphology, IR luminosity and environment of AGN hosts
(EDP Sciences, 2019-10-14) Ramón Pérez, M.; Bongiovanni, Á.; Pérez García, A. M.; Cepa, J.; Nadolny, J.; Pintos Castro, I.; Lara López, M. A.; Alfaro, Emilio J.; Castañeda, H. O.; Cerviño, M.; De Diego, J. A.; Fernández Lorenzo, M.; Gallego, J.; González, J. J.; González Serrano, J. I.; Oteo Martínez, R.; Povic, M.; Sánchez Portal, M.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709
Aims. We take advantage of the capabilities of the OSIRIS Tunable Emission Line Object (OTELO) survey to select and study the AGN population in the field. In particular, we aim to perform an analysis of the properties of these objects, including their demography, morphology, and IR luminosity. Focusing on the population of Hα emitters at z ∼ 0.4, we also aim to study the environments of AGN and non-AGN galaxies at that redshift.
methods. We make use of the multiwavelength catalogue of objects in the field compiled by the OTELO survey, unique in terms of minimum flux and equivalent width. We also take advantage of the pseudo-spectra built for each source, which allow the identification of emission lines and the discrimination of different types of objects.
Results. We obtained a sample of 72 AGNs in the field of OTELO, selected with four different methods in the optical, X-rays, and mid-infrared bands. We find that using X-rays is the most efficient way to select AGNs. An analysis was performed on the AGN population of OTELO in order to characterise its members. At z ∼ 0.4, we find that up to 26% of our Hα emitters are AGNs. At that redshift, AGNs are found in identical environments to non-AGNs, although they represent the most clustered group when compared to passive and star-forming galaxies. The majority of our AGNs at any redshift were classified as late-type galaxies, including a 16% proportion of irregulars. Another 16% of AGNs show signs of interactions or mergers. Regarding the infrared luminosity, we are able to recover all the luminous infrared galaxies (LIRGs) in the field of OTELO up to z ∼ 1.6. We find that the proportion of LIRGs and ultra-luminous infraed galaxies (ULIRGs) is higher among the AGN population, and that ULIRGs show a higher fraction of AGNs than LIRGs.
