  We numerically investigate dynamical evolution of a merger between a central
massive black hole (MBH) and a gas clump with the mass of $10^6$ $-$ $10^7$
$M_{\odot}$ in the central tens pc of a galactic bulge. We found that strong
tidal gravitational field of the MBH transforms the initial spherical clump
into a moderately thick gaseous disk (or torus) around the MBH. The developed
disk is also found to show rotation, essentially because the tidal field
changes efficiently the orbital angular momentum of the clump into intrinsic
angular momentum of the disk. Furthermore about a few percent of gas mass
(corresponding to a few $10^5$ $M_{\odot}$) in the clump is found to be
transferred to the central sub-parsec region around the MBH within an order of
$10^6$ yr. We thus suggest that successive merging of gas clumps onto a MBH can
not only be associated closely with the formation of nuclear disk around the
MBH but also can provide gas fuel for the MBH.

Astrophysics