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On the Cosmic Evolution of the Scaling Relations Between Black Holes and Their Host Galaxies: Broad-Line Active Galactic Nuclei in the zCOSMOS Survey

Merloni, A. and Bongiorno, A. and Bolzonella, M. and Brusa, M. and Civano, F. and Comastri, A. and Elvis, M. and Fiore, F. and Gilli, R. and Hao, H. and Jahnke, K. and Koekemoer, A. M. and Lusso, E. and Mainieri, V. and Mignoli, M. and Miyaji, T. and Renzini, A. and Salvato, M. and Silverman, J. and Trump, J. and Vignali, C. and Zamorani, G. and Capak, P. and Lilly, S. J. and Sanders, D. and Taniguchi, Y. and Bardelli, S. and Carollo, C. M. and Caputi, K. and Contini, T. and Coppa, G. and Cucciati, O. and de la Torre, S. and de Ravel, L. and Franzetti, P. and Garilli, B. and Hasinger, G. and Impey, C. and Iovino, A. and Iwasawa, K. and Kampczyk, P. and Kneib, J.-P. and Knobel, C. and Kovač, K. and Lamareille, F. and Le Borgne, J.-F. and Le Brun, V. and Le Fèvre, O. and Maier, C. and Pello, R. and Peng, Y. and Perez Montero, E. and Ricciardelli, E. and Scodeggio, M. and Tanaka, M. and Tasca, L. A. M. and Tresse, L. and Vergani, D. and Zucca, E. (2010) On the Cosmic Evolution of the Scaling Relations Between Black Holes and Their Host Galaxies: Broad-Line Active Galactic Nuclei in the zCOSMOS Survey. Astrophysical Journal, 708 (1). pp. 137-157. ISSN 0004-637X.

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We report on the measurement of the physical properties (rest-frame K-band luminosity and total stellar mass) of the hosts of 89 broad-line (type-1) active galactic nuclei (AGNs) detected in the zCOSMOS survey in the redshift range 1 < z < 2.2. The unprecedented multi-wavelength coverage of the survey field allows us to disentangle the emission of the host galaxy from that of the nuclear black hole in their spectral energy distributions (SEDs). We derive an estimate of black hole masses through the analysis of the broad Mg II emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project. We found that, as compared to the local value, the average black hole to host-galaxy mass ratio appears to evolve positively with redshift, with a best-fit evolution of the form (1 + z)^[(0.68±0.12)^(+0.6)_(-0.3)], where the large asymmetric systematic errors stem from the uncertainties in the choice of initial mass function, in the calibration of the virial relation used to estimate BH masses and in the mean QSO SED adopted. On the other hand, if we consider the observed rest-frame K-band luminosity, objects tend to be brighter, for a given black hole mass, than those on the local M_(BH)-M_K relation. This fact, together with more indirect evidence from the SED fitting itself, suggests that the AGN hosts are likely actively star-forming galaxies. A thorough analysis of observational biases induced by intrinsic scatter in the scaling relations reinforces the conclusion that an evolution of the M_(BH)-M_* relation must ensue for actively growing black holes at early times: either its overall normalization, or its intrinsic scatter (or both) appear to increase with redshift. This can be interpreted as signature of either a more rapid growth of supermassive black holes at high redshift, a change of structural properties of AGN hosts at earlier times, or a significant mismatch between the typical growth times of nuclear black holes and host galaxies. In any case, our results provide important clues on the nature of the early co-evolution of black holes and galaxies and challenging tests for models of AGN feedback and self-regulated growth of structures.

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Additional Information:© 2010 American Astronomical Society. Print publication: Issue 1 (2010 January 1); received 2009 July 14; accepted for publication 2009 October 30; published 2009 December 9. This research was supported by the DFG cluster of excellence “Origin and Structure of the Universe.” We thank the anonymous referee for carefully reading the manuscript and providing us with insightful and constructive remarks. We also thank R. Decarli, F. Fontanot, O. Gerhard, J. Greiner, P. Hopkins, S. Komossa, N. Menci, P. Monaco, H. Netzer, R. Saglia, L. Wisotzki, J.-H. Woo for their useful comments and suggestions. The HST COSMOS Treasury program was supported through NASA grant HST-GO-09822. We thank Tony Roman, Denise Taylor, and David Soderblom for their assistance in planning and scheduling of the extensive COSMOS observations. We gratefully acknowledge the contributions of the entire COSMOS collaboration consisting of more than 80 scientists. More information on the COSMOS survey is available at∼cosmos. It is a pleasure to acknowledge the excellent services provided by the NASA IPAC/ IRSA staff (Anastasia Laity,AnastasiaAlexov, Bruce Berriman, and John Good) in providing online archive and server capabilities for the COSMOS data sets. In Italy, this work was partly supported by an INAF contract PRIN/2007/ and an ASI grant ASI/COFIS/WP3110 I/026/07/0; in Mexico by the CONACyT grant program 83564 and PAPIIT IN110209; in Germany by the Bundesministerium f¨ur Bildung und Forschung/Deutsches Zentrum f¨ur Luft und Raumfahrt and the Max Planck Society.
Funding AgencyGrant Number
DFG cluster of excellence “Origin and Structure of the Universe”UNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)PRIN/2007/
ASIASI/COFIS/WP3110 I/026/07/0;
Consejo Nacional de Ciencia y Tecnología (CONACyT)83564
Programa de Apoyo a Proyectos de Investigación e Innovación (PAPIIT)IN110209
Bundesministerium für Bildung und Forschung/Deutsches Zentrum für Luft und RaumfahrtUNSPECIFIED
Max Planck SocietyUNSPECIFIED
Subject Keywords:cosmology: observations; galaxies: active; galaxies: evolution; quasars: emission lines
Record Number:CaltechAUTHORS:20100121-092925225
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Official Citation:On the Cosmic Evolution of the Scaling Relations Between Black Holes and Their Host Galaxies: Broad-Line Active Galactic Nuclei in the zCOSMOS Survey A. Merloni, A. Bongiorno, M. Bolzonella, M. Brusa, F. Civano, A. Comastri, M. Elvis, F. Fiore, R. Gilli, H. Hao, K. Jahnke, A. M. Koekemoer, E. Lusso, V. Mainieri, M. Mignoli, T. Miyaji, A. Renzini, M. Salvato, J. Silverman, J. Trump, C. Vignali, G. Zamorani, P. Capak, S. J. Lilly, D. Sanders, Y. Taniguchi, S. Bardelli, C. M. Carollo, K. Caputi, T. Contini, G. Coppa, O. Cucciati, S. de la Torre, L. de Ravel, P. Franzetti, B. Garilli, G. Hasinger, C. Impey, A. Iovino, K. Iwasawa, P. Kampczyk, J.-P. Kneib, C. Knobel, K. Kovač, F. Lamareille, J. -F. Le Borgne, V. Le Brun, O. Le Fèvre, C. Maier, R. Pello, Y. Peng, E. Perez Montero, E. Ricciardelli, M. Scodeggio, M. Tanaka, L. A. M. Tasca, L. Tresse, D. Vergani, and E. Zucca 2010 ApJ 708 137-157 doi: 10.1088/0004-637X/708/1/137
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17258
Deposited By: Jason Perez
Deposited On:21 Jan 2010 21:19
Last Modified:06 Jul 2015 20:37

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