X-ray spectral evolution of microquasars during soft-to-hard state transitions

We propose to perform (as a ToO) a series of 4x10ks+2x40 ks jointXMMNewton/NuSTAR observations (spaced by a few days) of a microquasar duringits outburst decline phase to follow its broadband Xray spectral evolution withan unprecedented precision. We will perform simultaneous radio, optical and IRobservations to observe the reactivation of the jet. This will allow us i) tocarefully investigate the physical/geometrical changes of the disc/corona systemthrough the transition and ii) to reveal the drivers of thequenching/reappearance of the jets during the state transitions and how theyconnect to the properties of the accretion flow. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]