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Faculty Publications, Department of Physics and Astronomy

Dust

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Full-Text Articles in Physics

Modelling Continuum Optical And Ultraviolet Polarization Of Active Galactic Nuclei, René W. Goosmann, C. Martin Gaskell Jun 2005

Modelling Continuum Optical And Ultraviolet Polarization Of Active Galactic Nuclei, René W. Goosmann, C. Martin Gaskell

Faculty Publications, Department of Physics and Astronomy

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 ...


The Nuclear Reddening Curve For Active Galactic Nuclei And The Shape Of The Infrared To X-Ray Spectral Energy Distribution, C. Martin Gaskell, René W. Goosmann, Robert R. J. Antonucci, David H. Whysong Nov 2004

The Nuclear Reddening Curve For Active Galactic Nuclei And The Shape Of The Infrared To X-Ray Spectral Energy Distribution, C. Martin Gaskell, René W. Goosmann, Robert R. J. Antonucci, David H. Whysong

Faculty Publications, Department of Physics and Astronomy

We present extinction curves derived from the broad emission lines and continua of samples of 72 radio-loud and 1018 radio-quiet active galactic nuclei (AGNs). The curves are significantly flatter in the UV than curves for the local interstellar medium. The reddening curves for the radio-quiet Large Bright Quasar Survey quasars are slightly steeper than those of the radio-loud quasars in the UV, probably because of additional reddening by dust farther out in the host galaxies of the former. The UV extinction curves for the radio-loud AGNs are very flat. This is explicable with slight modifications to standard Mathis-Rumpl-Nordsieck dust models ...