A molecular outflow in the Circinus galaxy

From previous work on the Circinus galaxy we postulated that approximate to 50% of the molecular gas in this type 2 Seyfert nucleus is distributed in a sub-kiloparsec circumnuclear ring, probably associated with the ongoing s tar-burst. In addition to this, we postulated the possible presence of a mo lecular outflow along the galaxy's minor axis. In this work we use a modifi ed version of the routine used previously (Curran et al. 1998), in order to model this feature. From our results we believe that a 90 degrees wide out flow, which constitutes approximate to 40% of the molecular gas within the central +/-600 pc, extends to a distance of approximate to +/-500 pc along the rotation axis of the ring with a maximum velocity of approximate to 190 km s(-1). The bulk velocity, which is somewhat lower than this, gives an e stimate of greater than or similar to 10(7)L. for the mechanical luminosity of the outflow. Armed with a model of the molecular gas distribution, and the fact that the large scale molecular ring appears to be perpendicular to the outflow/radio jets, we modelled how the CO luminosity varies with ring and outflow inclination i.e. Seyfert type. Our results show that in the ca se of a ring+outflow system, we expect very little difference in the lumino sities of a face-on and an identical edge-on system. In the case of a ring only distribution however, we do expect, due to "hole" in the gas, slightly more emission from a sufficiently close edge-on system, but still not enou gh to account for the differences in CO luminosities which have been observ ed between type 1 and type 2 Seyferts. This result supports the notion that something more than mere orientation comes into play when explaining these differences, thus having major implications for the unified theories of ac tive galactic nuclei.