1 research outputs found
Black Hole, Jet, and Disk: The Universal Engine
In this paper I review the results of our ongoing project to investigate the
coupling between accretion disk and radio jet in galactic nuclei and stellar
mass black holes. We find a good correlation between the UV bump luminosity and
the radio luminosities of AGN, which improves upon the usual [OIII]/radio
correlations. Taking mass and energy conservation in the jet/disk system into
account we can successfully model the correlation for radio-loud and radio-weak
quasars. We find that jets are comparable in power to the accretion disk
luminosity, and the difference between radio-loud and radio-weak may correspond
to two natural stages of the relativistic electron distribution -- assuming
that radio weak quasars have jets as well. The distribution of flat- and
steep-spectrum sources is explained by bulk Lorentz factors gamma_j ~ 5-10. The
absence of radio-loud quasars below a critical optical luminosity coincides
with the FR I/FR II break and could be explained by a powerdependent,
``closing'' torus. This points towards a different type of obscuring torus in
radio-loud host galaxies which might be a consequence of past mergers (e.g. by
the temporary formation of a binary black-hole). Interaction of the jet with
the closing torus might in principle also help to make a jet radio-loud.
Turning to stellar-mass black holes we find that galactic jet sources can be
described with the same coupled jet/disk model as AGN which is suggestive of
some kind of universal coupling between jet and accretion disk around compact
objects.Comment: to appear in ``Jets from Stars and Galactic Nuclei'', Springer
Lecture Notes, plain TeX, 16 pages, also at
http://www.astro.umd.edu/~hfalcke/publications.htm