Latest results from CERES/NA45

In this talk latest results from the analysis of $e^{+}e^{-}$ pairs emitted in Pb + Au collisions at 40 AGeV/c and a combined analysis of all data available at 158 AGeV/c are presented. The enhancement of low-mass $e^{+}e^{-}$ pairs $(m_{ee}>0.2 GeV/c^{2})$ with respect to the expected yield from hadron decays first reported at 158 AGeV/c is also found at 40 AGeV/c and is even larger there. Comparing to various theoretical models based on $\pi^{+}\pi^{-}$ annihilation, the data can only be reproduced, if the properties of the intermediate $\rho$ in the hot and dense medium are modified. Theoretically, the modification is linked to baryon density rather than temperature. Constraints from hadron data taken at the same beam energies indeed indicate a fireball evolution along a trajectory of higher baryon density at 40 AGeV/c, consistent with the observed larger enhancement factor.