Abstract
We have used VLBI HI absorption imaging to search for evidence for a circumnuclear atomic structure in five radio galaxies. Of these, we have found that two, (PKS 2322-123 and 1946+708), are very symmetric on parsec scales and exhibit strong evidence for a circumnuclear torus, confirming the prediction of the unified scheme. The two nearby extended radio galaxies NGC 5128 and NGC 315, on the other hand, have asymmetric core-jet morphologies on parsec scales, and their HI absorption profiles appear to arise from gas in the host galaxy which is not associated with the AGN at all. This is also consistent with the unified scheme of AGN. One remaining source, NGC 3894, also has symmetric jets, but has a very complicated HI structure which changes on parsec scales. This source requires further study.
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