  The correlation, found in nearby galaxies, between black hole mass and
stellar bulge mass implies that the formation of these two components must be
related. Here we report submillimeter photometry of eight x--ray absorbed
active galactic nuclei which have luminosities and redshifts characteristic of
the sources that produce the bulk of the accretion luminosity in the universe.
The four sources with the highest redshifts are detected at 850 microns, with
flux densities between 5.9 and 10.1 milliJanskies, and hence are ultraluminous
infrared galaxies. Interpreting the submillimeter flux as emission from dust
heated by starbursts, these results suggest that the majority of stars in
spheroids were formed at the same time as their central black holes built up
most of their mass by accretion, accounting for the observed demography of
massive black holes in the local universe. The skewed rate of submillimeter
detection with redshift is consistent with a high redshift epoch of star
formation in radio quiet active galactic nuclei, similar to that seen in radio
galaxies.
