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Evidence for merger remnants in early-type host galaxies of low-redshift QSOs

Bennert, Nicola and Canalizo, Gabriela and Jungwiert, Bruno and Stockton, Alan and Schweizer, Francois and Peng, Chien Y. and Lacy, Mark (2008) Evidence for merger remnants in early-type host galaxies of low-redshift QSOs. Astrophysical Journal, 677 (2). pp. 846-857. ISSN 0004-637X. doi:10.1086/529068.

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We present results from a pilot HSTACS deep imaging study in broadband Vof five low-redshift QSO host galaxies classified in the literature as ellipticals. The aim of our study is to determine whether these early-type hosts formed at high redshift and have since evolved passively, or whether they have undergone relatively recent mergers that may be related to the triggering of the nuclear activity. We perform two-dimensional modeling of the light distributions to analyze the host galaxies’morphology.We find that,while each host galaxy is reasonablywell fitted by a deVaucouleurs profile, the majority of them (4/5) reveal significant fine structure such as shells and tidal tails. These structures contribute between ~5% and 10% to the total V-band luminosity of each host galaxy within a region of r~3r_(eff) and are indicative of merger events that occurred between a few hundred Myr and a Gyr ago. These timescales are comparable to starburst ages in the QSO hosts previously inferred from Keck spectroscopy. Our results thus support a consistent scenario in which most of the QSO host galaxies suffered mergers with accompanying starbursts that likely also triggered the QSO activity in some way, but we are also left with considerable uncertainty on physical mechanisms that might have delayed this triggering for several hundred Myr after the merger.

Item Type:Article
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URLURL TypeDescription
Canalizo, Gabriela0000-0003-4693-6157
Lacy, Mark0000-0002-3032-1783
Additional Information:© 2008. The American Astronomical Society. Received 2007 October 10; accepted 2008 January 2. We thank the anonymous referee for valuable comments helping to improve the paper. Support for HST program 10421 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by The Association of Universities for Research in Astronomy, Inc., under NASA contract NAS526555. Additional support was provided by the National Science Foundation, under grant AST 05-07450. B. J. is also supported by grant LC06014 of the Czech Ministry of Education and by Research Plan AV0Z10030501 of the Academy of Sciences of the Czech Republic. C. Y. P. is grateful for support from the HIA Plaskett fellowship and the STScI Institute/Giacconi fellowship. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Funding AgencyGrant Number
NSFAST 05-07450
Academy of Sciences of the Czech RepublicAV0Z10030501
Subject Keywords:galaxies : active; galaxies : evolution; galaxies : interactions; quasars : general
Issue or Number:2
Record Number:CaltechAUTHORS:BENapj08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13840
Deposited By: Ruth Sustaita
Deposited On:15 Jul 2009 22:27
Last Modified:08 Nov 2021 22:41

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