The fraction of galaxies that contain active nuclei and their accretion rates |
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Authors: | MJ Page |
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Institution: | Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT |
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Abstract: | We investigate the relationship between the present-day optical luminosity function of galaxies and the X-ray luminosity function of Seyfert 1s to determine the fraction of galaxies that host Seyfert 1 nuclei and their Eddington ratios. The local type 1 active galactic nuclei (AGN) X-ray luminosity function is well reproduced if ~1 per cent of all galaxies are type 1 Seyferts which have Eddington ratios of ~10?3. However, in such a model the X-ray luminosity function is completely dominated by AGN in E and S0 galaxies, contrary to the observed mix of Seyfert host galaxies. To obtain a plausible mix of AGN host galaxy morphologies requires that the most massive black holes in E and S0 galaxies accrete with lower Eddington ratios, or have a lower incidence of Seyfert activity, than the central black holes of later-type galaxies. |
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Keywords: | accretion accretion discs galaxies: active galaxies: luminosity function mass function |
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