  A recent analysis of HST optical images of 34 nearby early-type active
galaxies and of a matched sample of 34 inactive galaxies - both drawn from the
Palomar survey - shows a clear excess of nuclear dusty structures (filaments,
spirals and disks) in the active galaxies. This result supports the association
of the dusty structures with the material which feeds the supermassive black
hole (hereafter SMBH). Among the inactive galaxies there is instead an excess
of nuclear stellar disks. As the active and inactive galaxies can be considered
two phases of the "same" galaxy, the above findings and dust morphologies
suggest an evolutionary scenario in which external material (gas and dust) is
captured to the nuclear region where it settles and ends up feeding the active
nucleus and replenishing the stellar disk - which is hidden by the dust in the
active galaxies - with new stars. This evolutionary scenario is supported by
recent gas kinematics of the inner few hundred parsecs of NGC1097, which shows
streaming motions (with velocities ~ 50 km/s) towards the nucleus along spiral
arms. The implied large scale mass accretion rate is much larger than the one
derived in previous studies for the nuclear accretion disk, but is just enough
to accumulate one million solar masses over a few million years in the nuclear
region, thus consistent with the recent finding of a young circumnuclear
starburst of one million solar masses within 9 parsecs from the nucleus in this
galaxy.
