Does the Jet Production Efficiency of Radio Galaxies Control Their
  Optical AGN Types?
  The jet production efficiency of radio galaxies can be quantified by
comparison of their kinetic jet powers P_jet and Bondi accretion powers P_B.
These two parameters are known to be related linearly, with the jet power
resulting from the Bondi power by multiplication with an efficiency factor of
order 1%. Using a recently published (Nemmen + Tchekhovskoy 2014) high-quality
sample of 27 radio galaxies, I construct a P_B-P_jet diagram that includes
information on optical AGN types as far as available. This diagram indicates
that the jet production efficiency is a function of AGN type: Seyfert 2
galaxies seem to be systematically (with a false alarm probability of 0.043%)
less efficient, by about one order of magnitude, in powering jets than Seyfert
1 galaxies, LINERs, or the remaining radio galaxies. This suggests an
evolutionary sequence from Sy2s to Sy1s and LINERs, controlled by an interplay
of jets on the one hand and dust and gas in galactic nuclei on the other hand.
When taking this effect into account, the P_B-P_jet relation is probably much
tighter intrinsically than currently assumed.
