Dilepton production at SIS energies with the GiBUU transport model

We present dilepton spectra from nucleus-nucleus collisions at SIS energies, which were simulated with the GiBUU transport model in a resonance-model approach. These spectra are compared to the data published by the HADES collaboration. We argue that the interpretation of dilepton spectra at SIS energies critically depends on the couplings between the ρ meson and the baryonic resonances.