The cosmic growth of the active black hole population at 1 < z < 2 in zCOSMOS, VVDS and SDSS

A. Schulze, A. Bongiorno, I. Gavignaud, M. Schramm, J. Silverman, A. Merloni, G. Zamorani, M. Hirschmann, V. Mainieri, L. Wisotzki, F. Shankar, F. Fiore, A. M. Koekemoer, G. Temporin

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)2085-2111
Number of pages27
JournalMonthly Notices of the Royal Astronomical Society
Volume447
Issue number3
DOIs
Publication statusPublished - 2015

Fingerprint

active galactic nuclei
distribution functions
luminosity
accretion
census
mass ratios
intervals
cycles
simulation
distribution
rate

Keywords

  • Galaxies: active
  • Galaxies: nuclei
  • Quasars: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Schulze, A. ; Bongiorno, A. ; Gavignaud, I. ; Schramm, M. ; Silverman, J. ; Merloni, A. ; Zamorani, G. ; Hirschmann, M. ; Mainieri, V. ; Wisotzki, L. ; Shankar, F. ; Fiore, F. ; Koekemoer, A. M. ; Temporin, G. / The cosmic growth of the active black hole population at 1 < z < 2 in zCOSMOS, VVDS and SDSS. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 447, No. 3. pp. 2085-2111.
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abstract = "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.",
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Schulze, A, Bongiorno, A, Gavignaud, I, Schramm, M, Silverman, J, Merloni, A, Zamorani, G, Hirschmann, M, Mainieri, V, Wisotzki, L, Shankar, F, Fiore, F, Koekemoer, AM & Temporin, G 2015, 'The cosmic growth of the active black hole population at 1 < z < 2 in zCOSMOS, VVDS and SDSS', Monthly Notices of the Royal Astronomical Society, vol. 447, no. 3, pp. 2085-2111. https://doi.org/10.1093/mnras/stu2549

The cosmic growth of the active black hole population at 1 < z < 2 in zCOSMOS, VVDS and SDSS. / Schulze, A.; Bongiorno, A.; Gavignaud, I.; Schramm, M.; Silverman, J.; Merloni, A.; Zamorani, G.; Hirschmann, M.; Mainieri, V.; Wisotzki, L.; Shankar, F.; Fiore, F.; Koekemoer, A. M.; Temporin, G.

In: Monthly Notices of the Royal Astronomical Society, Vol. 447, No. 3, 2015, p. 2085-2111.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The cosmic growth of the active black hole population at 1 < z < 2 in zCOSMOS, VVDS and SDSS

AU - Schulze, A.

AU - Bongiorno, A.

AU - Gavignaud, I.

AU - Schramm, M.

AU - Silverman, J.

AU - Merloni, A.

AU - Zamorani, G.

AU - Hirschmann, M.

AU - Mainieri, V.

AU - Wisotzki, L.

AU - Shankar, F.

AU - Fiore, F.

AU - Koekemoer, A. M.

AU - Temporin, G.

PY - 2015

Y1 - 2015

N2 - 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.

AB - 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.

KW - Galaxies: active

KW - Galaxies: nuclei

KW - Quasars: general

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U2 - 10.1093/mnras/stu2549

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