Orientation and accretion in a representative sample of active galactic nuclei

Abstract

We highlight a representative sample of active galactic nuclei selected independent of orientation. The defining characteristic of the selection is sophisticated matching between the $0.1<z<0.6$ Sloan Digital Sky Survey quasars from the Seventh Data Release to the Westerbork Northern Sky Survey at 325 MHz and the subsequent application of a total radio luminosity cut. The resulting sample is complete down to the limiting luminosity and unbiased by orientation. Compared to orientation samples in the literature this approach yields less bias with redshift, relatively more lobe-dominated sources including those with radio lobes and no visible core, and a distribution of radio core dominance that is consistent with expectations from a uniform distribution of inclinations with solid angle. We measure properties of the optical spectra, and use the sample to investigate the orientation dependence of the velocity width of the broad H$\beta$ emission line. We recover the known orientation dependence, but the sharp envelope of previous studies where only edge-on sources display the broadest lines, is absent. Scatter in this diagram is not attributable solely to black hole mass, Eddington ratio, or contamination in the sample from compact steep spectrum sources. A physical framework for quasar beaming and a disk-like broad-line region can describe the representative sample when it is expanded to include additional parameters, in particular jet properties and the broad-line region velocity field. These points serve to illustrate the critical role of sample selection in the interpretation of observable properties as indicators of physical parameters of quasar central engines.

arXiv comment28 pages, 10 figures, 6 tables, submitted to ApJ

References in corpus (41)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The Sloan Digital Sky Survey: Technical Summary
• A Catalog of Quasar Properties from SDSS DR7
• The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
• The Sloan Digital Sky Survey Quasar Catalog IV. Fifth Data Release
• Unification of Luminous Type 1 Quasars through CIV Emission
• The diversity of quasars unified by accretion and orientation
• On the Nature of Soft X-ray Weak Quasi-Stellar Objects
• The unusual emission line spectrum of IZw1
• The New Generation Atlas of Quasar Spectral Energy Distributions from Radio to X-rays
• Searching for the Physical Drivers of the Eigenvector 1 Correlation Space
• A Unified Catalog of Radio Objects Detected by NVSS, FIRST, WENSS, GB6, and SDSS
• The FIRST Radio-Loud Broad Absorption Line QSO and Evidence for a Hidden Population of Quasars
• AN IMPROVED MEASURE OF QUASAR ORIENTATION
• The quasar fraction in low-frequency selected complete samples and implications for unified schemes
• The Quasar Main Sequence explained by the combination of Eddington ratio, metallicity and orientation
• Orientation dependency of broad-line widths in quasars and consequences for black-hole mass estimation
• $\Lambda$CDM Cosmology for Astronomers
• Double Lobed Radio Quasars from the Sloan Digital Sky Survey
• An updated catalogue of giant radio sources
• A Large Systematic Search for Close Supermassive Binary and Rapidly Recoiling Black Holes - II. Continued Spectroscopic Monitoring and Optical Flux Variability
• Clues to Quasar Broad Line Region Geometry and Kinematics
• Correlations of Quasar Optical Spectra with Radio Morphology
• Radio Loud AGN in the Context of the Eigenvector 1 Parameter Space
• The Properties of Post-Starburst Quasars Based on Optical Spectroscopy
• The orientation dependence of quasar single-epoch black hole mass scaling relationships
• Orientation effects in quasar spectra: The broad- and narrow-line regions
• A robust derivation of the tight relationship of radio core dominance to inclination angle in high redshift 3CRR sources
• The Viewing Angles of Broad Absorption Line Versus Unabsorbed Quasars
• The Optical and Ultraviolet Emission-Line Properties of Bright Quasars with Detailed Spectral Energy Distributions
• The behavior of quasar C IV emission-line properties with orientation
• Radio-optical scrutiny of compact AGN: Correlations between properties of pc-scale jets and optical nuclear emission
• Orientation and quasar black hole mass estimation
• The orientation dependence of quasar spectral energy distributions
• Comparing different indicators of quasar orientation
• Radio jet structures at ~100 parsec and larger scales of the $\gamma$-ray-emitting narrow-line Seyfert 1 galaxy PMN J0948+0022
• Main trends of the quasar main sequence -- effect of viewing angle
• Does Size Matter? The Underlying Intrinsic Size Distribution of Radio Sources and Implications for Unification by Orientation
• Determining Quasar Orientation
• Investigating orientation effects considering angular resolution for a sample of radio-loud quasars using VLA observations
• Quasar emission lines, radio structures and radio unification