1120011

We propose to perform a long INTEGRAL observation of 700 ks of the Seyfert 1 galaxy NGC 5548 simultaneously with an already accepted XMM-Newton pointing during a unique and very large multi-wavelength monitoring of this source. The high energy capabilities of INTEGRAL will permit: 1) to complete the long-term light curve of the 20--60 keV flux of NGC 5548 and 2) to provide the best possible hard X-ray/soft gamma-ray spectrum of this object. As experienced from a previous very successful campaign led by our group on the Seyfert 1 Mrk 509 we need precise knowledge of the hard X-ray/soft gamma-ray band. On the one hand the hard X-ray/soft gamma-ray light curve is of prime importance for the characterization of the ionizing radiation critical information for an accurate time-dependent modeling of the warm-absorber properties that will be observed in detail with XMM-Newton. On the other hand the hard X-ray/soft gamma-ray spectrum is crucial to constrain the physical parameters of the Comptonizing corona responsible for the bulk of the X-ray emission. When combined with XMM-Newton lower-energy information it allows also to correctly disentangle the different spectral components present in the UV soft X medium X-ray and gamma-ray bands and in consequence to better understand their origins. [truncated! Please see actual data for full text]