  Broad hydroxyl (OH) absorption-lines in the 1667 MHz and 1665 MHz transition
towards the central region of NGC 3079 have been observed at high resolution
with the European VLBI Network (EVN). Velocity fields of two OH absorption
components were resolved across the unresolved nuclear radio continuum of ~10
parsecs. The velocity field of the OH absorption close to the systemic velocity
shows rotation in nearly the same sense as the edge-on galactic-scale molecular
disk probed by CO(1-0) emission. The velocity field of the blue-shifted OH
absorption displays a gradient in almost the opposite direction. The
blue-shifted velocity field represents a non-rotational component, which may
trace an outflow from the nucleus, or material driven and shocked by the
kiloparsec-scale superbubble. This OH absorption component traces a structure
that does not support a counter-rotating disk suggested on the basis of the
neutral hydrogen absorption.

Astrophysics