A Look at What Is (and Isn't) Known About Quasar Broad Line Regions and How Narrow-Line Seyfert 1 Galaxies Fit In

Abstract

The evidence is reviewed that the Broad Line Region (BLR) probably has two distinct components located at about the same distance from the central black hole. One component, BLR II, is optically-thick, low-ionization emission at least some of which arises from a disc and the other, BLR I, is probably optically-thin emission from a more spherically symmetric halo or atmosphere. The high Fe II/H-beta ratios seen in Narrow-Line Seyfert 1 galaxies (NLS1s) are not due to strong Fe II emission, as is commonly thought, but to unusually weak Balmer emission, probably caused by higher densities. NLS1s probably differ from non-NLS1s because of the higher density of gas near the black hole. This produces a higher accretion rate, a denser BLR, and a view of the central regions that is more face-on.

Contributed talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-workshop

References in corpus (5)

• Dynamics of Broad-Emission Line Region in NGC 5548: Hydromagnetic Wind Model versus Observations
• Rejection of the Binary Broad-Line Region Interpretation of Double-Peaked Emission Lines in Three Active Galactic Nuclei
• Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XII. Ground-Based Monitoring of 3C 390.3
• Evidence for Binary Orbital Motion of a Quasar Broad-Line Region
• Reverberation Mapping and the Disk Wind Model of the Broad Line Region

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• High metal content of highly accreting quasars
• Determining Inclinations of Active Galactic Nuclei Via Their Narrow-Line Region Kinematics - II. Correlation With Observed Properties
• The Case for Optically-Thick High Velocity Broad Line Region Gas in Active Galactic Nuclei
• Probing the Ionizing Continuum of Narrow-Line Seyfert 1 Galaxies. I.Observational Results
• An AGN Sample with High X-ray-to-optical Flux Ratio from RASS II.Optical Emission Line Properties of Seyfert 1 Type AGN
• A complete sample of Seyfert galaxies selected at 1/4 keV
• A comparative study of the physical properties for a representative sample of Narrow and Broad-line Seyfert galaxies