Nuclear Profiles of Markarian Galaxies and Seyfert Unification

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Session 23 -- Low-Luminosity AGNs
Display presentation, Tuesday, June 13, 1995, 9:20am - 6:30pm

[23.05] Nuclear Profiles of Markarian Galaxies and Seyfert Unification

C. H. Nelson, J. W. MacKenty (STScI), S. M. Simkin (MSU), R. E. Griffiths (JHU)

In unified models of active galaxies, Seyfert nuclei are surrounded by a dusty molecular torus. In type 2 Seyferts, where the torus blocks a direct view, the continuum and broad line region can only be detected through light scattered into the line of sight by material lying directly above the torus opening. These ``scattering mirrors'' may be as much as 100 parsecs across, as suspected in NGC 1068. Thus the nuclei of similar type 2 Seyferts should be at least partially resolved with HST out to distances of 200 Mpc. We have examined the nuclear profiles in our HST snapshot survey of Seyfert and non-Seyfert Markarian galaxies using WF/PC-1. We find that nuclei of Seyfert types 1 -- 1.5 are dominated by a strong point source, while those of Seyfert 2 and the non-Seyfert Markarian galaxies tend to be less distinct and often resolved. This result is in agreement with unified models of AGN. However, the similarity of the profiles of non-Seyfert Markarian and type 2 Seyfert nuclei suggests that circumnuclear star formation may also be an important component in the latter.

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