Dust torus around a supermassive black hole

This artist's impression shows the thick dust torus that
astronomers believe surrounds many supermassive
black holes and their accretion discs. When the
torus is seen edge-on as in this case, much of
the light emitted by the accretion disc is
blocked, creating a "hidden" black hole.

However, the sharp gamma-ray and X-ray eyes of Integral can peer through the
thick dust and identify the black hole within.
An Integral survey of the local universe found
few hidden black holes, implying that they must
have existed earlier (deeper) in the universe.