The OTELO survey

III. Demography, morphology, IR luminosity and environment of AGN hosts

¹ Instituto de Astrofísica de Canarias (IAC), 38200 La Laguna, Tenerife, Spain
e-mail: bongio@iac.es
² Departamento de Astrofísica, Universidad de La Laguna (ULL), 38205 La Laguna, Tenerife, Spain
³ Asociación Astrofísica para la Promoción de la Investigación, Instrumentación y su Desarrollo, ASPID, 38205 La Laguna, Tenerife, Spain
⁴ Centro de Astrobiología (CSIC/INTA), ESAC Campus, 28692 Villanueva de la Cañada, Madrid, Spain
⁵ Department of Astronomy & Astrophysics, University of Toronto, Canada
⁶ DARK, Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, Copenhagen 2100, Denmark
⁷ Instituto de Astrofísica de Andalucía, CSIC, 18080 Granada, Spain
⁸ Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ciudad de México, Mexico
⁹ Instituto de Astronomía, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
¹⁰ Departamento de Física de la Tierra y Astrofísica, Instituto de Física de Partículas y del Cosmos, IPARCOS. Universidad Complutense de Madrid, 28040 Madrid, Spain
¹¹ Instituto de Física de Cantabria (CSIC-Universidad de Cantabria), 39005 Santander, Spain
¹² Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
¹³ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹⁴ ISDEFE for European Space Astronomy Centre (ESAC)/ESA, PO Box 78, 28690 Villanueva de la Cañada, Madrid, Spain
¹⁵ Ethiopian Space Science and Technology Institute (ESSTI), Entoto Observatory and Research Center (EORC), Astronomy and Astrophysics Research Division, PO Box 33679, Addis Ababa, Ethiopia
¹⁶ Instituto de Radioastronomía Milimétrica (IRAM), Av. Divina Pastora 7, Núcleo Central, 18012 Granada, Spain

Received: 24 April 2018
Accepted: 25 March 2019

Abstract

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.