Watson, Linda C. and Martini, Paul and Dasyra, Kalliopi M. and Bentz, Misty C. and Ferrarese, Laura and Peterson, Bradley M. and Pogge, Richard W. and Tacconi, Linda J. (2008) First stellar velocity dispersion measurement of a luminous quasar host with Gemini North laser guide star adaptive optics. Astrophysical Journal Letters, 682 . L21-L24. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20090729-154905662
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We present the first use of the Gemini North laser guide star adaptive optics (LGS AO) system and an integral field unit (IFU) to measure the stellar velocity dispersion of the host of a luminous quasar. The quasar PG 1426+015 (z =0.086) was observed with the Near-Infrared Integral Field Spectrometer (NIFS) on the 8 m Gemini North telescope in the H band as part of the Science Verification phase of the new ALTAIR LGS AO system. The NIFS IFU and LGS AO are well suited for host studies of luminous quasars because one can achieve a large ratio of host to quasar light. We have measured the stellar velocity dispersion of PG 1426+015 from 0.1" to 1" (0.16 to 1.6 kpc) to be 217 ± 15 km s^(-1) based on high signal-to-noise ratio measurements of Si i, Mg i, and several CO band heads. This new measurement is a factor of 4 more precise than a previous measurement obtained with long-slit spectroscopy and good, natural seeing, yet was obtained with a shorter net integration time. We find that PG 1426+015 has a velocity dispersion that places it significantly above the M_(BH)^(-σ) relation of quiescent galaxies and lower luminosity active galactic nuclei with black hole masses estimated from reverberation mapping. We discuss several possible explanations for this discrepancy that could be addressed with similar observations of a larger sample of luminous quasars.
|Additional Information:||© 2008. The American Astronomical Society. Received 2008 March 31; accepted 2008 June 11; published 2008 July 3. We thank Chad Trujillo, Tracy Beck, and Richard McDermid for assistance with the Gemini observations and Doug Simons, the Gemini Director, for granting us DD time to obtain additional template star observations. We also thank the anonymous referee for comments that clarified this work. We acknowledge support for this work from NSF through grant AST 06-04066 to the Ohio State University. L. C. W. is supported by an NSF Graduate Fellowship. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil), and SECYT (Argentina). These observations were obtained for program ID GN-2006B-SV-110.|
|Subject Keywords:||galaxies: active galaxies: kinematics and dynamics|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||07 Aug 2009 18:40|
|Last Modified:||26 Dec 2012 11:07|
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