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Host Galaxies of Active Nuclei

Host Galaxies of Active Nuclei - 272 483 However they do...

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Host Galaxies of Active Nuclei Some relation between galaxy and AGN properties might be expected, if only due to the depth of the stellar potential well and the amount of gas available for feeding the monster. Also important are connections between such properties as radio emission and its structure and the type of surrounding galaxy. Seyfert galaxies are, almost by definition, mostly in spirals and S0s (Simkin et al 1980 ApJ 237, 404; Heckman 1980 PASP 90, 241; Adams 1977 ApJSuppl 33, 19). Companions and distortions are often present (see p. 83). Outer faint rings are more common than in spirals overall, but as Seyferts concentrate to earlier types Sa,Sb, so do outer rings (R), so this may not be significant. There is little correlation among Seyferts between galaxy and nuclear properties, except that the most luminous AGN seem to prefer overluminous galaxies. The nuclear line widths (NLR) do not correlate with disk inclination, so they are not driven by galaxy kinematics (Yee 1983 ApJ
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Unformatted text preview: 272, 483). However, they do correlate in part with measures of the three-dimensional virial velocity (Whittle 1992 ApJSuppl, 79, 49), so there is a less direct connection. The probability of having a Seyfert nucleus rises for brighter galaxies (Meurs and Wilson 1984 A&A 136, 206). A few dwarf systems (like the SMC or even fainter) have Seyfert nuclei, down to objects with luminosity not much more than the brightest supergiant stars (Filippenko and Sargent 1989 ApJLett 342, L11). There is no obvious connection with overall H I content (Heckman et al 1978 ApJ 224, 745) except the profile anomalies associated with interactions. There have been reports, and considerable controversy, as to whether Seyfert hosts have higher star-formation rates near the nuclei than otherwise expected. SDSS spectra indicate that SFR does correlate with level of AGN activity, whioch may require that the bulge stars are built more or less contemporaneously with episodes of AGN activity....
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