  We study self-consistently the finite $T$ broadening of the $\rho$-meson and
its implications for dilepton emission in heavy ion-collisions. For this
purpose finite width effects at finite temperature due to the $\rho$-$\pi$
interaction are investigated in a self-consistent $\Phi$-functional approach.
The temperature dependence of the $\rho$-meson and pion spectral functions and
self-energies is discussed. The spectral functions show considerable broadening
in comparison with a perturbative calculation on the one-loop level. Using
these spectral functions, we make a comparison to dilepton emission data from
the CERES NA49 collaboration employing a parametrized fireball evolution model
of collision. We demonstrate that these non-perturbative finite width effects
are in-medium modifications relevant to the understanding of the enhancement of
the low invariant mass spectrum of dileptons emitted in A-A collisions.

Nuclear Theory