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dc.contributor.authorSmith, Jamesen_US
dc.contributor.authorRobinson, Andrewen_US
dc.contributor.authorAlexander, Daviden_US
dc.contributor.authorYoung, Stuarten_US
dc.contributor.authorAxon, Daviden_US
dc.contributor.authorCorbett, Elizabethen_US
dc.date.accessioned2006-05-26T17:30:18Zen_US
dc.date.available2006-05-26T17:30:18Zen_US
dc.date.issued2004-05en_US
dc.identifier.citationMonthly Notices of the Royal Astronomical Society 350 (2004) 140en_US
dc.identifier.issn1365-2966en_US
dc.identifier.urihttp://hdl.handle.net/1850/1882en_US
dc.descriptionRIT community members may access full-text via RIT Libraries licensed databases: http://library.rit.edu/databases/
dc.description.abstractWe have identified 12 Seyfert 1 galaxies that exhibit optical polarization spectra similar to those of Seyfert 2 galaxies in which polarized broad-lines are detected. We present new spectropolarimetric observations of 3 of them: Was 45, Mrk 231 and NGC 3227. These objects appear to be polarized as a result of far-field scattering in the polar illumination cones of the circum-nuclear torus. We estimate that they represent between 10 and 30 per cent of the Seyfert 1 population; they are found amongst all the main spectroscopic sub-types, including narrow-line Seyfert 1 galaxies. We have shown elsewhere that Seyfert 1 nuclei more commonly have polarization characteristics that can be attributed to scattering by a compact ‘equatorial’ scattering region located inside the torus. We propose that both equatorial and polar scattering regions are present in all Seyfert galaxies and argue that the observed range of polarization properties can be broadly understood as an orientation effect. In this scheme, polar-scattered Seyfert 1 galaxies represent the transition between unobscured (the majority of type 1) and obscured (type 2) Seyferts. They are viewed through the upper layers of the torus and are thus subject to moderate extinction (AV≈1–4 mag) sufficient to suppress polarized light from the equatorial scattering region, but not the broad wings of the Balmer lines. The orientation of the polarization position angle relative to the radio source is broadly consistent with the two-component scattering model. More generally, we find that amongst Seyferts 1 galaxies, parallel, perpendicular and intermediate orientations of the polarization PA relative to the radio axis occur roughly in the proportions 2:1:1. (Refer to PDF file for exact formulas).en_US
dc.description.sponsorshipJES acknowledges financial support from PPARC.en_US
dc.format.extent637515 bytesen_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.publisherBlackwell Publishing: Monthly Notices of the Royal Astronomical Societyen_US
dc.relation.ispartofseriesvol. 350en_US
dc.relation.ispartofseriesp. 140en_US
dc.subjectGalaxies-activeen_US
dc.subjectGalaxies-Seyferten_US
dc.titleSeyferts on the edge: Polar scattering and orientation-dependent polarization in Seyfert 1 nucleien_US
dc.typeArticleen_US
dc.identifier.urlhttp://dx.doi.org/10.1111/j.1365-2966.2004.07610.x


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