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Spectacular shells in the host galaxy of the QSO MC2 1635+119

Canalizo, Gabriela and Bennert, Nicola and Jungwiert, Bruno and Stockton, Alan and Schweizer, François and Lacy, Mark and Peng, Chien (2007) Spectacular shells in the host galaxy of the QSO MC2 1635+119. Astrophysical Journal, 669 (2). pp. 801-809. ISSN 0004-637X.

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We present deep HST ACS images and Keck spectroscopy of MC2 1635+119, a QSO hosted by a galaxy previously classified as an undisturbed elliptical galaxy. Our new images reveal dramatic shell structure indicative of a merger event in the relatively recent past. The brightest shells in the central regions of the host are distributed alternately in radius, with at least two distinct shells on one side of the nucleus and three on the other, out to a distance of ~13 kpc. The light within the five shells comprises ~6% of the total galaxy light. Lower surface brightness ripples or tails and other debris extend out to a distance of ~65 kpc. A simple N-body model for a merger reproduces the inner shell structure and gives an estimate for the age of the merger of between ~30 Myr and ~1.7 Gyr, depending on a range of reasonable assumptions. While the inner shell structure is suggestive of a minor merger, the total light contribution from the shells and extended structures is more indicative of a major merger. The spectrum of the host galaxy is dominated by a population of intermediate age (~1.4 Gyr), indicating a strong starburst episode that may have occurred at the time of the merger event. We speculate that the current QSO activity may have been triggered in the recent past by either a minor merger, or by debris from an older (~Gyr) major merger that is currently "raining" back into the central regions of the merger remnant.

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Canalizo, Gabriela0000-0003-4693-6157
Lacy, Mark0000-0002-3032-1783
Additional Information:© 2007 The American Astronomical Society. Received 2007 June 18; accepted 2007 July 19. We thank S. Charlot and G. Bruzual for providing access to their models prior to publication and the referee for helpful comments. Support for program GO-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, Incorporated, under NASA contract NAS5-26555. Additional support was provided by the National Science Foundation, under grant AST 0507450. B. J. acknowledges support by grant LC06014 of the Czech Ministry of Education and by Research Plan AV0Z10030501 of the Academy of Sciences of the Czech Republic. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Space Telescope Science InstituteUNSPECIFIED
Ministry of Education (Czech Republic)LC06014
Academy of Sciences of the Czech RepublicAV0Z10030501
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:galaxies: active; galaxies: evolution; galaxies: interactions; quasars: general; quasars: individual (MC2 1635+119)
Issue or Number:2
Record Number:CaltechAUTHORS:CANapj07
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13784
Deposited By: Tony Diaz
Deposited On:13 Jul 2009 17:17
Last Modified:07 Nov 2019 15:14

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