AGN host galaxies at redshift z ˜ 0.7: Peculiar or not?
Por:
Böhm A., Wisotzki L., Bell E.F., Jahnke K., Wolf C., Bacon D., Barden M., Gray M.E., Hoeppe G., Jogee S., McIntosh D.H., Peng C.Y., Robaina A.R., Balogh M., Barazza F.D., Caldwell J.A.R., Heymans C., Häußler B., Van Kampen E., Lane K., Meisenheimer K., Sánchez S.F., Taylor A.N., Zheng X.
Publicada:
1 ene 2013
Resumen:
Aims. We perform a quantitative morphological comparison between the hosts of active galactic nuclei (AGN) and quiescent galaxies at intermediate redshifts (z ? 0.7). The imaging data are taken from the large HST/ACS mosaics of the GEMS and STAGES surveys. Our main aim is to test whether nuclear activity at this cosmic epoch is triggered by major mergers. Methods. Using images of quiescent galaxies and stars, we created synthetic AGN images to investigate the impact of an optical nucleus on the morphological analysis of AGN hosts. Galaxy morphologies are parameterized using the asymmetry index A, the concentration index C, the Gini coefficient G, and the M20 index. A sample of ~200 synthetic AGN was matched to 21 real AGN in terms of redshift, host brightness, and host-to-nucleus ratio to ensure a reliable comparison between active and quiescent galaxies. Results. The optical nuclei strongly affect the morphological parameters of the underlying host galaxy. Taking these effects into account, we find that the morphologies of the AGN hosts are clearly distinct from galaxies undergoing violent gravitational interactions. Indeed, the host galaxy distributions in morphological descriptor space are more similar to undisturbed galaxies than to major mergers. Conclusions. Intermediate-luminosity (LX ? 1044 erg/s) AGN hosts at z ? 0.7 show morphologies similar to the general population of massive galaxies with significant bulges at the same redshifts. If major mergers are the driver of nuclear activity at this epoch, the signatures of gravitational interactions fade rapidly before the optical AGN phase starts, making them undetectable on single-orbit HST images, at least with usual morphological descriptors. This could be investigated in future synthetic observations created from numerical simulations of galaxy-galaxy interactions. © ESO 2013.
Filiaciones:
Böhm A.:
Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, 6020 Innsbruck, Austria
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
Wisotzki L.:
Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
Bell E.F.:
University of Michigan, Department of Astronomy, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48105, United States
Jahnke K.:
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Wolf C.:
Department of Physics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH, United Kingdom
Bacon D.:
Institute of Cosmology and Gravitation, University of Portsmouth, Hampshire-Terrace, Portsmouth, PO1 2EG, United Kingdom
Barden M.:
Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, 6020 Innsbruck, Austria
Gray M.E.:
School of Physics and Astronomy, University of Nottingham, University-Park, Nottingham NG7 2RD, United Kingdom
Hoeppe G.:
Department of Anthropology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
Jogee S.:
Department of Astronomy, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712-0259, United States
McIntosh D.H.:
Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110, United States
Peng C.Y.:
Giant Magellan Telescope Organization, 251 South Lake Avenue, Pasadena, CA 91101, United States
Robaina A.R.:
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Institut de Ciéncies Del Cosmos, University of Barcelona, 08028 Barcelona, Spain
Balogh M.:
Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada
Barazza F.D.:
Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
Caldwell J.A.R.:
University of Texas, McDonald Observatory, Fort Davis, TX 79734, United States
Heymans C.:
Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, United Kingdom
Häußler B.:
School of Physics and Astronomy, University of Nottingham, University-Park, Nottingham NG7 2RD, United Kingdom
Van Kampen E.:
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen, Germany
Lane K.:
School of Physics and Astronomy, University of Nottingham, University-Park, Nottingham NG7 2RD, United Kingdom
Meisenheimer K.:
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Sánchez S.F.:
Centro Hispano Aleman de Calar Alto, C/Jesus Durban Remon 2-2, 04004 Almeria, Spain
Taylor A.N.:
Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, United Kingdom
Zheng X.:
Purple Mountain Observatory, National Astronomical Observatories, Chinese Academy of Sciences, 210008 Nanjing, China
Bronze
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