Propagating Mach Cones in a Viscous Quark-Gluon Plasma

I will discuss the space-time distribution of energy and momentum deposited by a fast parton traversing a perturbative quark-gluon plasma (arXiv:0805.0385 [hep-ph]). I use this distribution as a source term for the linearized hydrodynamical equations of the medium and present the resulting dynamics for three different values of the shear viscosity to entropy density ratio, $\eta/s$: $1/4\pi$, $3/4\pi$ and $6/4\pi$. I show that well defined Mach cones are found for $\eta/s = 1/4\pi, 3/4\pi$ but the conical structure begins to smear out for $\eta/s = 6/4\pi$.