A Caltech Library Service

The Environments of Active Galactic Nuclei within the zCOSMOS Density Field

Silverman, J. D. and Kovač, K. and Knobel, C. and Lilly, S. and Bolzonella, M. and Lamareille, F. and Mainieri, V. and Brusa, M. and Cappelluti, N. and Peng, Y. and Hasinger, G. and Zamorani, G. and Scodeggio, M. and Contini, T. and Carollo, C. M. and Jahnke, K. and Kneib, J.-P. and Le Fevre, O. and Bardelli, S. and Bongiorno, A. and Brunner, H. and Caputi, K. and Civano, F. and Comastri, A. and Coppa, G. and Cucciati, O. and de la Torre, S. and de Ravel, L. and Elvis, M. and Finoguenov, A. and Fiore, F. and Franzetti, P. and Garilli, B. and Gilli, R. and Griffiths, R. and Iovino, A. and Kampczyk, P. and Koekemoer, A. and Le Borgne, J.-F. and Le Brun, V. and Maier, C. and Mignoli, M. and Pello, R. and Perez Montero, E. and Ricciardelli, E. and Tanaka, M. and Tasca, L. and Tresse, L. and Vergani, D. and Vignali, C. and Zucca, E. and Bottini, D. and Cappi, A. and Cassata, P. and Marinoni, C. and McCracken, H. J. and Memeo, P. and Meneux, B. and Oesch, P. and Porciani, C. and Salvato, M. (2009) The Environments of Active Galactic Nuclei within the zCOSMOS Density Field. Astrophysical Journal, 695 (1). pp. 171-182. ISSN 0004-637X.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The impact of environment on active galactic nucleus (AGN) activity up to z ~ 1 is assessed by utilizing a mass-selected sample of galaxies from the 10k catalog of the zCOSMOS spectroscopic redshift survey. We identify 147 AGN by their X-ray emission as detected by XMM-Newton from a parent sample of 7234 galaxies. We measure the fraction of galaxies with stellar mass M_* > 2.5 × 10^(10) M_⊙ that host an AGN as a function of local overdensity using the 5th, 10th, and 20th nearest neighbors that cover a range of physical scales (~1-4 Mpc). Overall, we find that AGNs prefer to reside in environments equivalent to massive galaxies with substantial levels of star formation. Specifically, AGNs with host masses between 0.25 and 1 × 10^(11) M_⊙ span the full range of environments (i.e., field to group) exhibited by galaxies of the same mass and rest-frame color or specific star formation rate. Host galaxies having M_* > 10^(11) M_⊙ clearly illustrate the association with star formation since they are predominantly bluer than the underlying galaxy population and exhibit a preference for lower-density regions analogous to Sloan Digital Sky Survey studies of narrow-line AGN. To probe the environment on smaller physical scales, we determine the fraction of galaxies (M_* > 2.5 × 10^(10) M _⊙) hosting AGNs inside optically selected groups, and find no significant difference with field galaxies. We interpret our results as evidence that AGN activity requires a sufficient fuel supply; the probability of a massive galaxy to have retained some sufficient amount of gas, as evidence by its ongoing star formation, is higher in underdense regions where disruptive processes (i.e., galaxy harassment, tidal stripping) are lessened.

Item Type:Article
Related URLs:
URLURL TypeDescription
McCracken, H. J.0000-0002-9489-7765
Additional Information:© 2009 The American Astronomical Society. Received 2008 October 24; accepted 2009 January 2; published 2009 March 30. We thank the referee and Paul Martini for constructive comments that significantly improved the paper. This work is fully based on observations undertaken at the European Southern Observatory (ESO) Very Large Telescope (VLT) under the Large Program 175.A-0839 (P.I.: Simon Lilly). Facilities: XMM, VLT:Melipal (VIMOS).
Group:COSMOS, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Southern Observatory175. A-0839
Subject Keywords:galaxies: active; quasars: general; X-rays: galaxies
Record Number:CaltechAUTHORS:20090916-110305188
Persistent URL:
Official Citation:The Environments of Active Galactic Nuclei within the zCOSMOS Density Field J. D. Silverman, K. Kovač, C. Knobel, S. Lilly, M. Bolzonella, F. Lamareille, V. Mainieri, M. Brusa, N. Cappelluti, Y. Peng, G. Hasinger, G. Zamorani, M. Scodeggio, T. Contini, C. M. Carollo, K. Jahnke, J.-P. Kneib, O. Le Fevre, S. Bardelli, A. Bongiorno, H. Brunner, K. Caputi, F. Civano, A. Comastri, G. Coppa, O. Cucciati, S. de la Torre, L. de Ravel, M. Elvis, A. Finoguenov, F. Fiore, P. Franzetti, B. Garilli, R. Gilli, R. Griffiths, A. Iovino, P. Kampczyk, A. Koekemoer, J.-F. Le Borgne, V. Le Brun, C. Maier, M. Mignoli, R. Pello, E. Perez Montero, E. Ricciardelli, M. Tanaka, L. Tasca, L. Tresse, D. Vergani, C. Vignali, E. Zucca, D. Bottini, A. Cappi, P. Cassata, C. Marinoni, H. J. McCracken, P. Memeo, B. Meneux, P. Oesch, C. Porciani, and M. Salvato 2009 ApJ 695 171-182 doi: 10.1088/0004-637X/695/1/171.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15877
Deposited By: Tony Diaz
Deposited On:02 Oct 2009 21:34
Last Modified:19 May 2017 19:33

Repository Staff Only: item control page