The cosmic growth of the active black hole population at 1 < z < 2 in zCOSMOS, VVDS and SDSS
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Archivos
Fecha
2015-03
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
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Editor
Oxford University Press
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Licencia CC
Atribución 4.0 Internacional (CC BY 4.0)
Licencia CC
https://academic-oup-com.recursosbiblioteca.unab.cl/mnras/article/447/3/2085/986154
https://creativecommons.org/licenses/by/4.0/deed.es
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
We present a census of the active black hole population at 1 < z < 2, by constructing the bivariate distribution function of black hole mass and Eddington ratio, employing a maximum likelihood fitting technique. The study of the active black hole mass function (BHMF) and the Eddington ratio distribution function (ERDF) allows us to clearly disentangle the active galactic nuclei (AGN) downsizing phenomenon, present in the AGN luminosity function, into its physical processes of black hole mass downsizing and accretion rate evolution. We are utilizing type-1 AGN samples from three optical surveys (VVDS, zCOSMOS and SDSS), that cover a wide range of 3 dex in luminosity over our redshift interval of interest. We investigate the cosmic evolution of the AGN population as a function of AGN luminosity, black hole mass and accretion rate. Compared to z = 0, we find a distinct change in the shape of the BHMF and the ERDF, consistent with downsizing in black hole mass. The active fraction or duty cycle of type-1 AGN at z ~ 1.5 is almost flat as a function of black hole mass, while it shows a strong decrease with increasing mass at z = 0. We are witnessing a phase of intense black hole growth, which is largely driven by the onset of AGN activity in massive SMBHs (supermassive black holes) towards z = 2. We finally compare our results to numerical simulations and semiempirical models and while we find reasonable agreement over certain parameter ranges, we highlight the need to refine these models in order to match our observations. © 2015 The Authors.
Notas
Indexación: Scopus
Palabras clave
Galaxies: active, Galaxies: nuclei, Quasars: general
Citación
Monthly Notices of the Royal Astronomical Society Volume 447, Issue 3, Pages 2085 - 21111 March 2015
DOI
10.1093/mnras/stu2549