  Obscured or narrow-line active galaxies offer an unobstructed view of the
quasar environment in the presence of a luminous and vigorously accreting black
hole. We exploit the large new sample of optically selected luminous
narrow-line active galaxies from the Sloan Digital Sky Survey at redshifts 0.1
< z < 0.45, in conjunction with follow-up observations with the Low Dispersion
Survey Spectrograph (LDSS3) at Magellan, to study the distributions of black
hole mass and host galaxy properties in these extreme objects. We find a narrow
range in black hole mass (<log M_BH/M_sun> = 8.0 +/- 0.7) and Eddington ratio
(<log L/L_Edd> = -0.7 +/- 0.7) for the sample as a whole, surprisingly similar
to comparable broad-line systems. In contrast, we infer a wide range in star
formation properties and host morphologies for the sample, from disk-dominated
to elliptical galaxies. Nearly one-quarter have highly disturbed morphologies
indicative of ongoing mergers. Unlike the black holes, which are apparently
experiencing significant growth, the galaxies appear to have formed the bulk of
their stars at a previous epoch. On the other hand, it is clear from the lack
of correlation between gaseous and stellar velocity dispersions in these
systems that the host galaxy interstellar medium is far from being in virial
equilibrium with the stars. While our findings cast strong doubt on the
reliability of substituting gas for stellar dispersions in high luminosity
active galaxies, they do provide direct evidence that luminous accreting black
holes influence their surroundings on a galaxy-wide scale.
