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D.M. Worrall (University of Bristol)
In the years since Seyfert galaxies and quasars were first discovered through optical and radio techniques, high-energy emission has become the defining characteristic of an Active Galactic Nucleus (AGN). Current X-ray missions are sufficiently sensitive at high energies to detect AGNs behind large intrinsic gas column densities, and so to test unified models. Grating spectroscopy can resolve even quite narrow Fe K\alpha lines, so associating them with an accretion disk or gas torus. AGNs with extended radio jets are of particular interest, since the jets signal source orientation. However, the jets extend into the cores, where they are faster and more compact. Special-relativistic effects then cause jet brightness and variability time-scales across the electromagnetic spectrum to be strong functions of jet orientation. Jet X-ray emission is confused, to varying degrees, with that from the central engine, but can be measured, at least in a statistical sense, through considerations of the multiwaveband spectrum and the level of intrinsic absorption. The rich high-energy structures found in jets which are resolved with Chandra and HST inform our interpretation of the inner structures.
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.