Astrophysics and Space Science

, Volume 248, Issue 1, pp 93–104

A Hypersonic Entrainment Model for the Ionization Cones of NGC1068

  • M. A. Dopita

DOI: 10.1023/A:1000596604962

Cite this article as:
Dopita, M.A. Astrophysics and Space Science (1997) 248: 93. doi:10.1023/A:1000596604962


I present a model for the ionization cones of NGC1068, and, by extension, for Seyfert Galaxies in general. In this, the cones represent the hypersonic interaction of a sheet of material expelled from close to the galactic nucleus with the interstellar medium of the galaxy. Such a model produces a turbulent magnetically-supported shearing mixing layer with a Kelvin-Helmholtz unstable outer boundary. This drives strong shocks into the dense wall material, and generates fast stand-off shocks in the entrainment flow. The EUV photons produced in the fast shock ionize both the wall material and the entrainment layer to generate the broad highly excited lines that are such a characteristic of the emission line spectrum. This model is consistent with the energy budget, the observed spectrum, the emission line widths, and provides sufficient column density to produce an electron scattering "mirror".

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • M. A. Dopita
    • 1
  1. 1.Mt. Stromlo and Siding Spring Observatories IASThe Australian National UniversityACTAustralia