Physical parameter eclipse mapping

We present a new Eclipse Mapping method for reconstructing the properties o f accretion discs in eclipsing catatclysmic variables. Physical Parameter E clipse Mapping reconstructs spatially resolved maps of physical parameters such as temperatures and surface densities by fitting observed eclipse ligh t curves at several wavelengths with the aid of a model describing the depe ndence of the disc spectrum on the physical parameters. Physical Parameter Eclipse Mapping has clear advantages over a classical approach for many app lications. Most importantly, all of the available spectrophotometric data c an be fitted simultaneously. The only drawback is the assumption of a physi cal model prior to the reconstructions. However, the method is very flexibl e in the choice of the spectral model, since the method itself does not dep end on the choice. Furthermore, physical considerations, observations and e xperience will help determine the model to be used. The analysis with synthetic data shows that reliable parameter distribution s can be obtained if the reconstruction behaviour of the model used is well understood. This means that the reconstructions are only as good as the mo del allows. In ambiguous parameter regions the method can (by definition) n ot give us the correct answer. However, in ambiguous-free zones, we show th at the method indeed gives us the correct answer.