Dilepton and Photon Emission Rates from a Hadronic Gas II

We extend our recent analysis of the dilepton and photon emission rates to the case of finite temperature and baryon density, within the context of a density expansion. To leading order, the effects of the baryon density are assessed using data (photon emission) or constraints from broken chiral symmetry (dilepton emission). Next to leading order effects are worked out, and their contribution qualitatively assessed. The opening of the $\pi N$ cut causes the photon rate to saturate the empirical photon yield of WA80, but may not be enough to fully account for the excess low mass dileptons seen at CERES.