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G. Canalizo (LLNL)
The commonly held view that QSOs are fueled in strong tidal interactions has up until now been mostly based on circumstantial evidence. Here we present high quality imaging and spectroscopic observations of a sample of low-redshift QSO host galaxies and interacting companions. These objects show signs of strong recent tidal interaction, and their spectra are successfully modeled by an underlying old population plus a superposed young instantaneous burst population. We obtain relative ages between stellar populations in various regions of the host and/or companion galaxies. These estimates, along with the dynamical ages implied by their tidal features, place constraints on the timescale for concentrating material in the nucleus, which in turn could provide the fuel for the QSO. Our results firmly establish the fact that at least some QSOs can be traced back to a merger and a starburst phase.
Part of this work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48, and was also partially supported by NSF under grant AST 95-29078.
The author(s) of this abstract have provided an email address for comments about the abstract: canalizo@igpp.ucllnl.org