The OTELO survey: a case study of [O III] λ 4959,5007 emitters at <z>=0.83

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 = 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 ∼5 × 10^(−19) erg s^(−1) cm^(2) and ∼6 Å, respectively. We are able to constrain the faint-end slope (α = −1.03 ± 0.08) of the observed LF ([O III]) at a mean redshift of z = 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* < 10^(10) Mͼ

Galaxy evolution studies observing emission line galaxies with the GTC

Emission line galaxies are the most easily detected and studied objects in the high redshift Universe. They are being used to trace the evolution of the critical observables of the Universe such as star formation rate densities, starburst properties, and abundances. The GTC will b e a very powerful tool for studying the evolution of emission line galaxy populations at different redshifts. Large surveys, such as OTELO, carried out with OSIRIS and extended by follow-up spectroscopic studies in the near infrared using EMIR will enable the GTC to make a major impact in extragalactic astronomy

Gran Telescopio Canarias observations of an overdense region of Lyman alpha emitters at z=6.5

We present the results of our search near the end of the Reionization Epoch for faint galaxies. This has been done using very deep OSIRIS images obtained at the Gran Telescopio Canarias (GTC). Our observations focus around two close, massive Lyman alpha emitters (LAEs) at redshift 6.5, discovered in the SXDS field within a large-scale overdense region. The total GTC observing time in three medium band filters (F883w35, F913w25 and F941w33) is over 34 h covering 7.0 x 8.5 arcmin(2) (or similar to 30 000 Mpc(3) at z = 6.5). In addition to the two spectroscopically confirmed LAEs in the field, we have identified 45 other LAE candidates. The preliminary luminosity function derived from our observations, assuming a spectroscopic confirmation success rate of 2/3 as in previous surveys, suggests this area is about 2 times denser than the general field galaxy population at z = 6.5. If confirmed spectroscopically, our results will imply the discovery of one of the earliest protoclusters in the Universe, which will evolve to resemble the most massive galaxy clusters today

Addendum. OTELO survey: optimal emission-line flux determination with OSIRIS/GTC (vol 122, pg 1495, 2010)

The following authors should be included in the author list of this article: E. Alfaro, J. Gallego, J. J. González, and J. I. González-Serrano. All of them are part of the OTELO project and were not listed in the original version of the article due to an oversight

Estudio de una muestra completa de galaxias con emisiones en Hα

Tesis de Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física de la Tierra, Astronomía y Astrofísica II, leída el 24-03-1995Este trabajo consiste en caracterizar la muestra de galaxias con emisión en h "alfa" obtenida de la exploración UCM. En total 272 objetos hasta un desplazamiento al rojo de 0.045 analizados espectroscópicamente. Cada uno de ellos fue clasificado según ocho tipos espectroscópicos. Principalmente (47%) se trata de galaxias con intensos procesos de formación estelar. Por otro lado, se ha encontrado un 43% de objetos de baja ionización que no se detectan con otras técnicas. Los diferentes tipos observados forman una suave gradación de procesos de formación estelar en la que la metalicidad y el parámetro de ionización son los parámetros fundamentales. En contra de los postulados por algunos autores no se ha encontrado ninguna galaxia de metalicidad menor a los valores conocidos. Las galaxias estudiadas se presentan con mayor frecuencia en zonas de densidad de galaxias intermedia. La función de luminosidad obtenida proporciona restricciones observacionales importantes a las teorías de formación y evolución de galaxias.Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEpu

The OTELO survey: a case study of [O III] λ4959,5007 emitters at <z> = 0.83 (Corrigendum)

© ESO 2020. Artículo firmado por 25 autores.Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEpu

Estudio de una muestra completa de galaxias con emisiones en Hα

Este trabajo consiste en caracterizar la muestra de galaxias con emisión en h "alfa" obtenida de la exploración UCM. En total 272 objetos hasta un desplazamiento al rojo de 0.045 analizados espectroscópicamente. Cada uno de ellos fue clasificado según ocho tipos espectroscópicos. Principalmente (47%) se trata de galaxias con intensos procesos de formación estelar. Por otro lado, se ha encontrado un 43% de objetos de baja ionización que no se detectan con otras técnicas. Los diferentes tipos observados forman una suave gradación de procesos de formación estelar en la que la metalicidad y el parámetro de ionización son los parámetros fundamentales. En contra de los postulados por algunos autores no se ha encontrado ninguna galaxia de metalicidad menor a los valores conocidos. Las galaxias estudiadas se presentan con mayor frecuencia en zonas de densidad de galaxias intermedia. La función de luminosidad obtenida proporciona restricciones observacionales importantes a las teorías de formación y evolución de galaxias

The OTELO survey as a morphological probe. Last ten Gyr of galaxy evolution. The mass-size relation up to z=2

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 multiwavelength 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 z_(phot) = 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

X-ray luminosity functions of different morphological and X-ray type AGN populations

Luminosity functions are one of the most important observational clues when studying galaxy evolution over cosmic time. In this paper we present the X-ray luminosity functions for X-ray detected AGN in the SXDS and GWS fields. The limiting fluxes of our samples are 9.0 ×10^(-15) and 4.8 ×10^(-16) erg cm^(-2) s^(-1) in the 0.5-7.0 keV band in the two fields, respectively. We carried out analysis in three X-ray bands and in two redshift intervals up to z≤1.4. Moreover, we derive the luminosity functions for different optical morphologies and X-ray types. We confirm strong luminosity evolution in all three bands, finding the most luminous objects at higher redshift. However, no signs of density evolution are found in any tested X-ray band. We obtain similar results for compact and early-type objects. Finally, we observe the “Steffen effect", where X-ray type-1 sources are more numerous at higher luminosities in comparison with type-2 sources

Polishing techniques for MEGARA pupil elements optics

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral-field and multi-object optical spectrograph for the 10.4m Gran Telescopio Canarias.. It will offer RFWHM ~6,000, 12,000 and 18,700 for the low- , mid- and high-resolution, respectively in the wavelength range 3650-9700Å. .The dispersive elements are volume phase holographic (VPH) gratings, sandwiched between two flat Fused Silica windows of high optical precision in large apertures. The design, based in VPHs in combination with Ohara PBM2Y prisms allows to keep the collimator and camera angle fixed. Seventy three optical elements are being built in Mexico at INAOE and CIO. For the low resolution modes, the VPHs windows specifications in irregularity is 1 fringe in 210mm x 170mm and 0.5 fringe in 190mm x 160mm. for a window thickness of 25 mm. For the medium and high resolution modes the irregularity specification is 2 fringes in 220mm x 180mm and 1 fringe in 205mm x 160mm, for a window thickness of 20mm. In this work we present a description of the polishing techniques developed at INAOE optical workshop to fabricate the 36 Fused Silica windows and 24 PBM2Y prisms that allows us to achieve such demanding specifications. We include the processes of mounting, cutting, blocking, polishing and testing