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Active galactic nucleus host galaxy morphologies in COSMOS

Gabor, J. M. and Impey, C. D. and Jahnke, K. and Simmons, B. D. and Trump, J. R. and Koekemoer, A. M. and Brusa, M. and Cappeluti, N. and Schinnerer, E. and Smolčić, V. and Salvato, M. and Rhodes, J. D. and Mobasher, B. and Capak, P. and Massey, R. and Leauthaud, A. and Scoville, N. (2009) Active galactic nucleus host galaxy morphologies in COSMOS. Astrophysical Journal, 691 (1). pp. 705-722. ISSN 0004-637X. doi:10.1088/0004-637X/691/1/705.

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We use Hubble Space Telescope/Advanced Camera for Surveys images and a photometric catalog of the Cosmic Evolution Survey (COSMOS) field to analyze morphologies of the host galaxies of ~400 active galactic nucleus (AGN) candidates at redshifts 0.3 < z < 1.0. We compare the AGN hosts with a sample of nonactive galaxies drawn from the COSMOS field to match the magnitude and redshift distribution of the AGN hosts. We perform two-dimensional surface brightness modeling with GALFIT to yield host galaxy and nuclear point source magnitudes. X-ray-selected AGN host galaxy morphologies span a substantial range that peaks between those of early-type, bulge-dominated and late-type, disk-dominated systems. We also measure the asymmetry and concentration of the host galaxies. Unaccounted for, the nuclear point source can significantly bias results of these measured structural parameters, so we subtract the best-fit point source component to obtain images of the underlying host galaxies. Our concentration measurements reinforce the findings of our two-dimensional morphology fits, placing X-ray AGN hosts between early- and late-type inactive galaxies. AGN host asymmetry distributions are consistent with those of control galaxies. Combined with a lack of excess companion galaxies around AGN, the asymmetry distributions indicate that strong interactions are no more prevalent among AGN than normal galaxies. In light of recent work, these results suggest that the host galaxies of AGN at these X-ray luminosities may be in a transition from disk-dominated to bulge-dominated, but that this transition is not typically triggered by major mergers.

Item Type:Article
Related URLs:
URLURL TypeDescription
Jahnke, K.0000-0003-3804-2137
Simmons, B. D.0000-0001-5882-3323
Koekemoer, A. M.0000-0002-6610-2048
Brusa, M.0000-0002-5059-6848
Schinnerer, E.0000-0002-3933-7677
Smolčić, V.0000-0002-3893-8614
Salvato, M.0000-0001-7116-9303
Rhodes, J. D.0000-0002-4485-8549
Capak, P.0000-0003-3578-6843
Massey, R.0000-0002-6085-3780
Leauthaud, A.0000-0002-3677-3617
Scoville, N.0000-0002-0438-3323
Additional Information:© 2009. The American Astronomical Society. Received 2008 May 12; accepted 2008 August 25; published 2009 January 19. Print publication: Issue 1 (2009 January 20). We gratefully acknowledge the contributions of the entire COSMOS collaboration consisting of more than 70 scientists. More information on the COSMOS survey is available at We also thank the anonymous, thorough referee for contributing to the quality of this work. J.G. would like to thank Romeel Dave, Rodger Thompson, and Ann Zabludoff for guidance and useful discussion, and Stéphanie Juneau for help with K-corrections. J.D.R. was supported by internal funding at the Jet Propulsion Laboratory, California Institute of Technology, operated under a contract with NASA. K.J. acknowledges support by the German DFG under grant SCHI 536/3-1 and through the DFG Emmy Noether-Program under grant JA 1114/3-1. Facilities: HST (ACS), Magellan: Baade (IMACS), XMM, VLA, MMT (Hectospec). Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc, under NASA contract NAS 5-26555; also based on data collected at: the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory under Large Program 175.A-0839, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation; the National Radio Astronomy Observatory which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc; and the Canada-France-Hawaii Telescope with MegaPrime/MegaCam operated as a joint project by the CFHT Corporation, CEA/DAPNIA, the National Research Council of Canada, the Canadian Astronomy Data Centre, the Centre National de la Recherche Scientifique de France, TERAPIX and the University of Hawaii.
Group:COSMOS, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)SCHI 536/3-1
Deutsche Forschungsgemeinschaft (DFG)JA 1114/3-1
NASANAS 5-26555
European Space AgencyUNSPECIFIED
European Southern Observatory175.A-0839
Subject Keywords:galaxies: active; galaxies: evolution; galaxies: interactions; galaxies: structure
Issue or Number:1
Record Number:CaltechAUTHORS:GABapj09
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13114
Deposited By: Archive Administrator
Deposited On:21 Jan 2009 22:41
Last Modified:08 Nov 2021 22:35

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