First Stellar Velocity Dispersion Measurement of a Luminous Quasar Host with Gemini North Laser Guide Star Adaptive Optics

Abstract

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 PG1426+015 (z=0.086) was observed with the Near-Infrared Integral Field Spectrometer (NIFS) on the 8m 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 PG1426+015 from 0.1'' to 1'' (0.16 kpc to 1.6 kpc) to be 217+/-15 km/s based on high signal-to-noise ratio measurements of Si I, Mg I, and several CO bandheads. This new measurement is a factor of four 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 PG1426+015 has a velocity dispersion that places it significantly above the M-sigma 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.

5 pages, 2 figures; accepted by ApJ Letters

References in corpus (6)

• The effect of radiation pressure on virial black hole mass estimates and the case of Narrow Line Seyfert 1 galaxies
• A Reverberation-Based Mass for the Central Black Hole in NGC 4151
• Dynamical properties of Ultraluminous Infrared Galaxies. II. Traces of dynamical evolution and end products of local ultraluminous mergers
• The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping
• Host dynamics and origin of Palomar-Green QSOs
• Orientation dependency of broad-line widths in quasars and consequences for black-hole mass estimation

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• The Black Hole Mass of NGC 4151. II. Stellar Dynamical Measurement from Near-Infrared Integral Field Spectroscopy
• Estimating Masses of Supermassive Black Holes in Active Galactic Nuclei from the Halpha Emission Line
• Medium Resolution Near-Infrared Spectra of the Host Galaxies of Nearby Quasars
• Quasar Host Galaxies and the $M_{SMBH}$ - ${\sigma }_{\ast }$ Relation
• What Drives the Bimodal Distribution of Eddington-Scaled Radio Luminosity in Nearby Early-Type Galaxies?