  We derive the space-time distribution of energy and momentum deposited by a
fast parton traversing a weakly coupled quark-gluon plasma by treating the fast
part on as the source of an external color field perturbing the medium. We then
use our result as a source term for the linearized hydrodynamical equations of
the medium. We show that the solution contains a sonic Mach cone and a
dissipative wake if the parton moves at a supersonic speed.
