High‐Resolution Imaging of the OH Megamaser Emission in IRAS 12032+1707 and IRAS 14070+0525

We present results from VLBA observations of the 1667 and 1665 MHz OH linesin the two OH megamaser galaxies IRAS12032+1707 and IRAS14070+0525. ForIRAS12032+1707 we also present Arecibo HI absorption data. Almost all OHemission previously detected by single dish observations has been recovered inIRAS12032+1707 and is found on a compact scale of <100 pc. The emission showsan ordered velocity field that is consistent with a single disk. However, thedata is also consistent with a scenario including two physically different gascomponents. We explore this possibility, in which the two strongest and mostblueshifted maser features are identified as the tangent points of acircumnuclear torus. The redshifted maser features would be extended in adirection perpendicular to the torus, which is in the direction of the mergercompanion. Thus, redshifted emission could be associated with an inflowtriggered by a tidal interaction. HI absorption covers the velocities of theredshifted maser emission, suggesting a common origin. In the second source,IRAS14070+0525, a large fraction of the OH emission is resolved out with theVLBA. We find no significant evidence of an ordered velocity field in thissource, but these results are inconclusive due to a very low signal-to-noiseratio.Comment: 10 pages, 7 Postscript figures, accepted by Ap