  We estimated black hole masses for 9 Seyfert 1 and 13 Seyfert 2 galaxies in
the Palomar and CfA bright Seyfert samples using the tight correlation between
black hole mass and bulge velocity dispersion. Combining other 13 Seyfert 1s
and 2 Seyfert 2s in these samples but with black hole masses measured recently
by reverberation mapping and stellar/gas dynamics, we studied the correlations
of black hole masses with radio loudness and bulge luminosities for a sample of
37 Seyfert galaxies. We found that if radio-loudness is measured using the
optical and radio luminosities of the nuclear components, the black hole masses
of radio-loud Seyfert 1s tend to increase with the radio-loudness. The black
hole masses of all Seyfert galaxies increase with the radio power, but Seyfert
galaxies have larger radio powers than nearby galaxies with the same black hole
masses. In addition, the correlation between black hole masses and bulge V-band
luminosities for Seyfert galaxies is consistent with that found for quasars and
normal galaxies. The combined sample of 37 Seyfert galaxies, 15 quasars and 30
normal galaxies suggests a possible universal nonlinear relation between black
hole and bulge masses, $M(BH) \propto M(bulge)^{1.74\pm0.14}$, which is
slightly steeper than that found recently by Laor (2001) for a smaller sample.
This nonlinear relation is supported by a larger sample including 65 Seyfert
galaxies. The different M(BH)/M(bulge) ratio for galaxies with different bulge
luminosities or different black hole masses may be explained by this relation.
These results are consistent with some theoretical implications and are
important for understanding the nature of radio emissions and the formation and
evolution of supermassive black holes and galaxies.
