2002A&A...387L..29H

Using the Effelsberg 100-m telescope, sensitive measurements of the H₂O megamaser in NGC 3079 are presented. During 2000-2001, ``high velocity'' features are seen that are red-shifted up to 225km/s with respect to the systemic velocity of the galaxy (V_LSR∼1120km/s). Symmetrically bracketing the systemic velocity, the H₂O emission covers a velocity range of ∼450km/s with only one potential narrow gap (∼20km/s) near the systemic velocity itself. Velocity drifts of individual components are not convincingly detected. It is shown that the presence of red-shifted emission and the absence of detectable velocity drifts are not inconsistent with the existence of a rotating circumnuclear maser disk at the very center of the galaxy. Significant differences in the overall line profile compared to NGC 4258 and a complex morphology of the radio continuum leave, however, space for scepticism.