High Resolution Imaging of the Cold Circumnuclear ISM and the Discovery of a OH kilo-Maser in NGC 1068

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Session 20 -- AGN Environments
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

[20.02] High Resolution Imaging of the Cold Circumnuclear ISM and the Discovery of a OH kilo-Maser in NGC 1068

J.F.Gallimore (STScI, U.Md.), S.A.Baum, C.P.O'Dea (STScI), E.Brinks (NRAO, Socorro), A.Pedlar (NRAL, Jodrell Bank)

and OH absorption viewed against the bright radio continuum structure in the Seyfert galaxy NGC 1068. All of the detected absorption is confined to a region southwest of the radio nucleus and arises from the inner galaxian disk. We confirm the presence of an offset shock front and post-shock compression of material inside the leading edge of the stellar bar. That this shock is offset implies that the inner Lindblad resonance lies interior to the 3~kpc starburst ``ring'' and that the ring may have formed at the corotation resonance. We also report the discovery of a main line OH ``kilo-''maser roughly coincident with the faded H$_2$O ``mega-''maser. In contrast to the red-shifted H$_2$O maser, the principle OH emission feature is blue- shifted with respect to $v_{sys}$ by 300 km s$^{-1}$. Weaker OH emission is also found centered near $v_{sys}$. We consider the possibility that this OH maser might arise in a dense circumnuclear torus posited to hide the Seyfert 1 nucleus.

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