AAS 195th Meeting, January 2000
Session 115. Seyferts and Other Mildly Active Galaxies
Display, Saturday, January 15, 2000, 9:20am-4:00pm, Grand Hall

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[115.02] Jet directions in Seyfert galaxies

H. R. Schmitt (STScI), A. L. Kinney (NASA Headquarters), C. J. Clarke, J. E. Pringle (IoA - Cambridge), J. S. Ulvestad (NRAO), R. R. J. Antonucci (UCSB)

We present the study of the relative angle between the accretion disk (or radio jet) and the galaxy disk for a sample of Seyfert galaxies selected from a mostly isotropic property, the 60\mum flux. For each galaxy we have a pair of points (i,\delta), which are the inclination of the galaxy relative to the line of sight, and the angle between the jet projected into the plane of the sky and the host galaxy major axis, respectively. This data is combined with a statistical technique to determine the distribution of \beta angles in 3 dimensions, the angle between the jet and the host galaxy plane axis. The analysis of the data, not differentiating between Seyfert 1's and 2's, showed that the observed distribution of i and \delta values can be well represented by a homogeneous \beta-distribution in the range 0\circ\leq\beta\leq90\circ. However, when we distinguished between Seyfert 1's and 2's, the models could not represent Seyfert 1's adequately. It was necessary to introduce viewing angle restrictions, that a galaxy can only be recognized as a Seyfert 1 if the angle between the jet and the line of sight (|\phi|) is smaller than a given angle \phic and that the galaxy inclination i is smaller than an angle ic, in order to have statistically acceptable models. This is a direct and independent confirmation of the underlying concepts of the Unified Model.

We discuss two main lines to explain the misalignment between the accretion disk axis and the host galaxy disk axis: i) feeding of the accretion disk by aligned inflow from the galaxy disk, with the posterior misalignment of the accretion disk (e.g. warping by self-irradiation instability, by the Bardeen-Petterson effect, or by a misaligned gravitational potential of a nuclear star cluster surrounding the black hole); ii) feeding of the accretion disk by misaligned gas inflow (e.g. misaligned minor mergers, capture of individual molecular clouds from the host galaxy).

This work was supported by NASA grants.

The author(s) of this abstract have provided an email address for comments about the abstract: schmitt@stsci.edu

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