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Modelling Continuum Optical And Ultraviolet Polarization Of Active Galactic Nuclei, René W. Goosmann, C. Martin Gaskell
Modelling Continuum Optical And Ultraviolet Polarization Of Active Galactic Nuclei, René W. Goosmann, C. Martin Gaskell
Department of Physics and Astronomy: Faculty Publications
We present results from a new Monte Carlo radiative transfer computer code, STOKES, developed to model polarization induced by scattering off free electrons and dust grains. STOKES is freely available on the web and can be used to model scattering in a wide variety of astrophysical situations. For edge-on (type-2) viewing positions, the polarization produced by a dusty torus alone is largely wavelength-independent.
This is because the torus is optically thick and the change in albedo with wavelength is slight. Wavelength-independent polarization therefore does not necessarily imply electron scattering. We are able to fully explain wavelength independent type-2 polarization without …
A Look At What Is (And Isn't) Known About Quasar Broad Line Regions And How Narrow-Line Seyfert 1s Fit In, C. Martin Gaskell
A Look At What Is (And Isn't) Known About Quasar Broad Line Regions And How Narrow-Line Seyfert 1s Fit In, C. Martin Gaskell
Department of Physics and Astronomy: Faculty Publications
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/Hβ 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 …