High-resolution radio observations of Seyfert galaxies in the extended 12-μm sample – II. The properties of compact radio components |
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| Authors: | Andy Thean Alan Pedlar Marek J Kukula Stefi A Baum Christopher P O'Dea |
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| Institution: | ;1Istituto di Radioastronomia del CNR, Via P. Gobetti 101, I–40129 Bologna, Italy;2Jodrell Bank Observatory, University of Manchester, Jodrell Bank, Macclesfield, Cheshire SK11 9DL;3Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ;4Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA |
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| Abstract: | We discuss the properties of compact nuclear radio components in Seyfert galaxies from the extended 12-μm AGN sample of Rush et al. Our main results can be summarized as follows.
Type 1 and type 2 Seyferts produce compact radio components which are indistinguishable in strength and aspect, indicating that their central engines are alike, as proposed by the unification model. Infrared IRAS fluxes are more closely correlated with low-resolution radio fluxes than high-resolution radio fluxes, suggesting that they are dominated by kiloparsec-scale, extranuclear emission regions; extranuclear emission may be stronger in type 2 Seyferts. Early-type Seyfert galaxies tend to have stronger nuclear radio emission than late-type Seyfert galaxies. V-shaped extended emission-line regions, indicative of 'ionization cones', are usually found in sources with large, collimated radio outflows. Hidden broad lines are most likely to be found in sources with powerful nuclear radio sources. Type 1 and type 2 Seyferts selected by their IRAS 12-μm flux densities have well-matched properties. |
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| Keywords: | galaxies: active galaxies: Seyfert galaxies: statistics infrared: galaxies radio continuum: galaxies |
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