Examinando por Autor "Gallego, J."

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Restringido
An ionized superbubble powered by a protocluster at z = 6.5
(Oxford Academics: Oxford University Press, 2020-03-18) Rodríguez Espinosa, J. M.; Mas Hesse, J. M.; Salvador Solé, E.; Calvi, R.; Manrique, Alberto; Chanchaiworawit, K.; Guzman, R.; Gallego, J.; Herrero, A.; Marín Franch, A.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Rodríguez Espinosa, J. M. [0000-0002-0674-1470]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We show herein that a proto-cluster of Ly α emitting galaxies, spectroscopically confirmed at redshift 6.5, produces a remarkable number of ionizing continuum photons. We start from the Ly α fluxes measured in the spectra of the sources detected spectroscopically. From these fluxes, we derive the ionizing emissivity of continuum photons of the protocluster, which we compare with the ionizing emissivity required to reionize the protocluster volume. We find that the sources in the protocluster are capable of ionizing a large bubble, indeed larger than the volume occupied by the protocluster. For various calculations, we have used the model AMIGA, in particular to derive the emissivity of the Lyman continuum photons required to maintain the observed volume ionized. Besides, we have assumed the ionizing photons escape fraction given by AMIGA at this redshift.
Acceso Abierto
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.
Acceso Abierto
MOS spectroscopy of protocluster candidate galaxies at z = 6.5
(Oxford Academics: Oxford University Press, 2019-08-16) Calvi, R.; Rodríguez Espinosa, J. M.; Mas hesse, J. M.; Chanchaiworawit, K.; Guzman, R.; Salvador Solé, E.; Gallego, J.; Herrero, A.; Manrique, Alberto; Marín Franch, A.; National Astronomical Research Institute of Thailand (NARIT); European Commission (EC); Ministry of Education, Culture, Sports, Science and Technology (MEXT); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Manríque, A. [0000-0001-5339-2659]; Gallego, J. [0000-0003-1439-7697]; Calvi, R. [0000-0002-1462-9462]; 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 ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548; Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos (ICCUB), MDM-2014-0369
The epoch corresponding to a redshift of z ∼ 6.5 is close to full re-ionization of the Universe, and early enough to provide an intriguing environment to observe the early stage of large-scale structure formation. It is also an epoch that can be used to verify the abundance of a large population of low luminosity star-forming galaxies that are deemed responsible for cosmic re-ionization. Here, we present the results of follow-up multi-object spectroscopy using OSIRIS at Gran Telescopio Canarias of 16 Ly α emitter (LAE) candidates discovered in the Subaru/XMM Newton Deep Survey. We have securely confirmed 10 LAEs with sufficient signal-to-noise ratio of the Ly α emission line. The inferred star formation rates of the confirmed LAEs are on the low side, within the range 0.9–4.7 M⊙ yr−1. However, they show relatively high Ly α rest frame equivalent widths. Finally we have shown that the mechanical energy released by the star formation episodes in these galaxies is enough to create holes in the neutral hydrogen medium such that Lyman continuum photons can escape to the intergalactic medium, thus contributing to the re-ionization of the Universe.
Acceso Abierto
Spatially Resolved Analysis of Neutral Winds, Stars, and Ionized Gas Kinematics with MEGARA/GTC: New Insights on the Nearby Galaxy UGC 10205
(Institute of Physics, 2020-02-06) Catalán Torrecilla, C.; Castillo Morales, Á; Gil de paz, A.; Gallego, J.; Carrasco, E.; Iglesias Páramo, J.; Cedazo, R.; Chamorro Cazorla, M.; Pascual, S.; García Vargas, M. L.; Cardiel, N.; Gómez Álvarez, P.; Pérez Calpena, A.; Martínez Delgado, I.; Dullo, B. T.; Coelho, P. R. T.; Bruzual, G.; Charlot, S.; Agencia Estatal de Investigación (AEI); Universidad Nacional Autónoma de México (UNAM); 0000-0002-8067-0164; 0000-0003-4964-3245; 0000-0001-6150-2854; 0000-0003-1439-7697; 0000-0003-2726-6370; 0000-0002-9351-6051; 0000-0002-9334-2979; 0000-0002-4140-0110; 0000-0003-1846-4826; 0000-0002-6971-5755; 0000-0003-3458-2275; 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
We present a comprehensive analysis of the multiphase structure of the interstellar medium (ISM) and the stellar kinematics in the edge-on nearby galaxy UGC 10205 using integral field spectroscopy (IFS) data taken with MultiEspectrografo en GTC de Alta Resolucion para Astronomia (MEGARA) at the GTC. We explore both the neutral and the ionized gas phases using the interstellar Na I D doublet absorption (LR-V setup, R similar to 6000) and the Ha emission line (HR-R setup, R similar to 18000), respectively. The high-resolution data show the complexity of the Ha emission-line profile revealing the detection of up to three kinematically distinct gaseous components. Despite of this fact, a thin-disk model is able to reproduce the bulk of the ionized gas motions in the central regions of UGC 10205. The use of asymmetric drift corrections is needed to reconciliate the ionized and the stellar velocity rotation curves. We also report the detection of outflowing neutral gas material blueshifted by similar to 87 km s(-1). The main physical properties that describe the observed outflow are a total mass M-out = (4.55 +/- 0.06) x 10(7) M-circle dot and a coldgas mass outflow rate (M)over dot(out) = 0.78 +/- 0.03 M-circle dot yr(-1). This work points out the necessity of exploiting highresolution IFS data to understand the multiphase components of the ISM and the multiple kinematical components in the central regions of nearby galaxies.
Acceso Abierto
The OTELO survey as a morphological probe. Last ten Gyr of galaxy evolution The mass–size relation up to z = 2
(EDP Sciences, 2021-03-12) Nadolny, J.; Bongiovanni, Á.; Cepa, J.; Cerviño, M.; Pérez García, A. M.; Povic, M.; Pérez Martínez, M.; De Diego, J. A.; Pintos Castro, I.; Alfaro, Emilio J.; Castañeda, H. O.; Gallego, J.; González, J. J.; González Serrano, J. I.; Lara López, M. A.; Padilla Torres, C. P.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); National Research Council (NRC); Ethiopian Space Science and Technology Institute (ESSTI); Nadolny, J. [0000-0003-1440-9061]; Centro de Excelencia Científica Severo Ochoa Instituto de Astrofísica de Andalucía CSIC, 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 morphology of galaxies provide us with a unique tool for relating and understanding other physical properties and their changes over the course of cosmic time. It is only recently that we have been afforded access to a wealth of data for an unprecedented number galaxies thanks to large and deep surveys. Aims. We present the morphological catalogue of the OTELO survey galaxies detected with the Hubble Space Telescope (HST)-ACS F814W images. We explore various methods applied in previous works to separate early-type (ET) and late-type (LT) galaxies classified via spectral energy distribution (SED) fittings using galaxy templates. Together with this article, we are releasing a catalogue containing the main morphological parameters in the F606W and F814W bands derived for more than 8000 sources. Methods. The morphological analysis is based on the single-Sérsic profile fit. We used the GALAPAGOS2 software to provide multi-wavelength morphological parameters fitted simultaneously in two HST-ACS bands. The GALAPAGOS2 software detects, prepares guess values for GALFIT-M, and provides the best-fitting single-Sérsic model in both bands for each source. Stellar masses were estimated using synthetic rest-frame magnitudes recovered from SED fittings of galaxy templates. The morphological catalogue is complemented with concentration indexes from a separate SExtractor dual, high dynamical range mode. Results. A total of 8812 sources were successfully fitted with single-Sérsic profiles. The analysis of a carefully selected sample of ∼3000 sources up to zphot = 2 is presented in this work, of which 873 sources were not detected in previous studies. We found no statistical evidence for the evolution of the low-mass end of mass–size relation for ET and LT since z = 2. Furthermore, we found a good agreement for the median size evolution for ET and LT galaxies, for a given stellar mass, with the data from the literature. Compared to previous works on faint field galaxies, we found similarities regarding their rest-frame colours as well as the Sérsic and concentration indices.
Acceso Abierto
The OTELO survey as a morphological probe. Last ten Gyr of galaxy evolution The mass–size relation up to z = 2
(EDP Sciences, 2021-03-12) Nadolny, J.; Bongiovanni, Á.; Cepa, J.; Cerviño, M.; Pérez García, A. M.; Povic, M.; Pérez Martínez, R.; Sánchez Portal, M.; De Diego, J. A.; Pintos Castro, I.; Alfaro, Emilio J.; Castañeda, H. O.; Gallego, J.; González, J. J.; González Serrano, J. I.; Lara López, M. A.; Padilla Torres, P.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Centre National de la Recherche Scientifique (CNRS); National Research Council (NRC); Ethiopian Space Science and Technology Institute (ESSTI); Nadolny, J. [0000-0003-1440-9061]; Pérez Martínez, R. [0000-0002-9127-5522]; González, J. J. [0000-0002-3724-1583]; Povic, M. [0000-0002-9766-6110]; Centro de Excelencia Científica Severo Ochoa Instituto de Astrofísica de Andalucía CSIC, 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 morphology of galaxies provide us with a unique tool for relating and understanding other physical properties and their changes over the course of cosmic time. It is only recently that we have been afforded access to a wealth of data for an unprecedented number galaxies thanks to large and deep surveys. Aims. We present the morphological catalogue of the OTELO survey galaxies detected with the Hubble Space Telescope (HST)-ACS F814W images. We explore various methods applied in previous works to separate early-type (ET) and late-type (LT) galaxies classified via spectral energy distribution (SED) fittings using galaxy templates. Together with this article, we are releasing a catalogue containing the main morphological parameters in the F606W and F814W bands derived for more than 8000 sources. Methods. The morphological analysis is based on the single-Sérsic profile fit. We used the GALAPAGOS2 software to provide multi-wavelength morphological parameters fitted simultaneously in two HST-ACS bands. The GALAPAGOS2 software detects, prepares guess values for GALFIT-M, and provides the best-fitting single-Sérsic model in both bands for each source. Stellar masses were estimated using synthetic rest-frame magnitudes recovered from SED fittings of galaxy templates. The morphological catalogue is complemented with concentration indexes from a separate SExtractor dual, high dynamical range mode. Results. A total of 8812 sources were successfully fitted with single-Sérsic profiles. The analysis of a carefully selected sample of ∼3000 sources up to zphot = 2 is presented in this work, of which 873 sources were not detected in previous studies. We found no statistical evidence for the evolution of the low-mass end of mass–size relation for ET and LT since z = 2. Furthermore, we found a good agreement for the median size evolution for ET and LT galaxies, for a given stellar mass, with the data from the literature. Compared to previous works on faint field galaxies, we found similarities regarding their rest-frame colours as well as the Sérsic and concentration indices.
Acceso Abierto
The OTELO survey Faint end of the luminosity function of [O II]3727 emitters at ⟨z⟩ = 1.43
(EDP Sciences, 2021-05-13) Cedrés, B.; Bongiovanni, Á.; Cerviño, M.; Nadolny, J.; Cepa, J.; De Diego, J. A.; Pérez García, A. M.; Gallego, J.; Lara López, M. A.; Sánchez Portal, M.; González Serrano, J. I.; Alfaro, E. J.; Navarro Martínez, R.; Pérez Martínez, R.; González, J. J.; Padilla Torres, C. P.; Castañeda, H. O.; González Otero, Mauro; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Agence Nationale de la Recherche (ANR); Pérez Martínez, R. [0000-0002-9127-5522]; Lara López, M. A. [0000-0001-7327-3489]; Cedrés, B. [0000-0002-7382-6407]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC (MDM-2017-0737)
Aims. In this paper, we aim to study the main properties and luminosity function (LF) of the [O II]3727 emitters detected in the OTELO survey in order to characterise the star formation processes in low-mass galaxies at z ∼ 1.43 and to constrain the faint-end of the LF. Methods. Here, we describe the selection method and analysis of the emitters obtained from narrow-band scanning techniques. In addition, we present several relevant properties of the emitters and discuss the selection biases and uncertainties in the determination of the LF and the star formation rate density (SFRD). Results. We confirmed a total of 60 sources from a preliminary list of 332 candidates as [O II]3727 emitters. Approximately 93% of the emitters have masses in the range of 108 < M*/M⊙ < 109. All of our emitters are classified as late-type galaxies, with a lower value of (u − v) when compared with the rest of the emitters of the OTELO survey. We find that the cosmic variance strongly affects the normalisation (ϕ*) of the LF and explains the discrepancy of our results when compared with those obtained from surveys of much larger volumes. However, we are able to determine the faint-end slope of the LF, namely, α = −1.42 ± 0.06, by sampling the LF down to ∼1 dex lower than in previous works. We present our calculation of the SFRD of our sample and compare it to the value obtained in previous studies from the literature.
Acceso Abierto
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.
Acceso Abierto
The OTELO survey II. The faint-end of the Hα luminosity function at z ∼ 0.40
(EDP Sciences, 2019-10-14) Ramón Pérez, M.; Bongiovanni, Á.; Pérez García, A. M.; Cepa, J.; Lara López, M. A.; De Diego, J. A.; Alfaro, Emilio J.; Castañeda, H. O.; Cerviño, M.; Fernández Lorenzo, M.; Gallego, J.; González, J. J.; González Serrano, J. I.; Nadolny, J.; Oteo Gómez, I.; Pérez Martínez, R.; Pintos Castro, I.; Povic, M.; Sánchez Portal, M.; Agencia Estatal de Investigación (AEI); 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
Aims. We take advantage of the capability of the OTELO survey to obtain the Hα luminosity function (LF) at z ∼ 0.40. Because of the deepest coverage of OTELO, we are able to determine the faint end of the LF, and thus better constrain the star formation rate and the number of galaxies at low luminosities. The AGN contribution to this LF is estimated as well. Methods. We make use of the multiwavelength catalogue of objects in the field compiled by the OTELO survey, which is 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. The Hα luminosity function at z ∼ 0.40 is obtained, which extends the current faint end by almost 1 dex, reaching minimal luminosities of log10Llim = 38.5 erg s−1 (or ∼0.002 M⊙ yr−1). The AGN contribution to the total Hα luminosity is estimated. We find that no AGN should be expected below a luminosity of log10L = 38.6 erg s−1. From the sample of non-AGN (presumably, pure SFG) at z ∼ 0.40 we estimated a star formation rate density of ρSFR = 0.012 ± 0.005 M⊙ yr−1 Mpc−3.
Acceso Abierto
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.
Acceso Abierto
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.
Acceso Abierto
The OTELO Survey: The Star Formation Rate Evolution of Low-mass Galaxies
(IOP Science Publishing, 2021-07-01) Cedrés, B.; Pérez García, A. M.; Pérez Martínez, R.; Cerviño, M.; Gallego, J.; Bongiovanni, Á.; Cepa, J.; Navarro Martínez, R.; Nadolny, J.; Lara López, M. A.; Agence Nationale de la Recherche (ANR); Cedrés, B. [0000-0002-7382-6407]; Gallego, J. [0000-0003-1439-7697]; Nadolny, J. [0000-0003-1440-9061]; Lara López, M. A. [0000-0001-7327-3489]
We present the analysis of a sample of Hα, Hβ, and [O ii] emission line galaxies from the OTELO survey, with masses typically below $\mathrm{log}({M}_{* }/{M}_{\odot })\sim 9.4$ and redshifts between z ∼ 0.4 and 1.43. We study the star formation rate, star formation rate density, and their number density and evolution with redshift. We obtain a robust estimate of the specific star formation rate—stellar mass relation based on the lowest-mass sample published so far. We also determine a flat trend of the star formation rate density (SFRD) and number density with redshift. Our results suggest a scenario of no evolution of the number density of galaxies, regardless of their masses, up to redshift z ∼ 1.4. This implies a gradual change of the relative importance of the star-forming processes, from high-mass galaxies to low-mass galaxies, with decreasing redshift. We also find little or no variation of the SFRD in the redshift range of 0.4 < z < 1.43.