We have mapped , for the first time , the full velocity extent of the water maser emission in NGC 3079 .
The largely north-south distribution of emission , aligned with a kpc-scale molecular disk , and the segregation of blue- and red-shifted emission on the sky are suggestive of a nearly edge-on molecular disk on pc-scales .
Positions and line-of-sight velocities of blue- and red-shifted maser emission are consistent with a central mass of \sim 2 \times 10 ^ { 6 } M _ { \sun } enclosed within a radius of \sim 0.4 pc .
The corresponding mean mass density of 10 ^ { 6.8 } M _ { \sun } pc ^ { -3 } is suggestive of a central black hole , which is consistent with the detection of hard X-ray excess ( 20 - 100 keV ) and an Fe K \alpha line from the nucleus .
Because the rotation curve traced by the maser emission is flat , the mass of the pc-scale disk is significant with respect to the central mass .
Since the velocity dispersion of the maser features does not decrease with radius and constitutes a large fraction of the orbital velocity , the disk is probably thick and flared .
The rotation curve and the physical conditions necessary to support maser emission imply a Toomre Q -parameter that is \ll 1 .
Thus , the disk is most likely clumpy , and we argue that it is probably forming stars .
Overall , the accretion disk in NGC 3079 stands in contrast to the compact , thin , warped , differentially rotating disk in the archetypal maser galaxy NGC 4258 .

We have also mapped radio continuum emission in the vicinity of the disk and identify a new , time-variable , non-thermal component ( E ) that is not collinear with the previously imaged putative jet .
Based on the large luminosity and the unusually steep spectrum ( \alpha < -2.1 ) , we exclude a radio supernova as the progenitor of E. However , because its spectrum is consistent with an aging electron energy distribution , E might be a rapidly cooling remnant , which may indicate that the jet axis wobbles .
Alternatively , considering its location , the component might mark a shock in a wide-angle outflow that is interacting with a dense ambient medium .
In this context , masers at high latitudes above the disk , mapped in this and previous studies , may be tracing an inward extension of the kpc-scale bipolar wide-angle outflow previously observed along the galactic minor axis .